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U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 113. 

L. O. HOWARD. Entomologist and Chief of Bureau. 



THE PRINCIPAL CACTUS INSECTS 
OF THE UNITED STATES. 



BY 

W. D. HUNTER. 

In Charge of Southern Field Crop Insect Investigations, 

F. C. PRATT, 

Late Assistant Entomologist, 
AND 

J. D. MITCHELL, 

Agent and Expert. 



Issued December 19, 1912. 







WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 113. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



THE PRINCIPAL CACTUS INSECTS 
OF THE UNITED STATES. 



BY 



W. D. HUNTER, 

In Charge of Southern Field Crop Insect Investigations, 

F. C. PRATT, 

Late Assistant Entomologist, 
AND 



J. D. MITCHELL, 

Agent and Expert. 



Issued December 19, 1912. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



BUREAU OF ENTOMOLOGY. 

L. O. Howard, Entomologist and Chief of Hunan. 

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. 

R. S. Clifton. Executive Assistant. 

W. F. Tastet, Chief Clerk. 

F.H.Chittenden, in charge of truck crop and stored product insect investigations. 

A. D. Hopkins, in charge of forest insect investigations. 

W. D. Hunter, in charge of southern field crop insect investigations. 

F. M. Webster, in charge of cereal and forage insect investigations. 

A. L. Quaintance, in charge of deciduous fruit insect investigations. 

E. F. Phillips, in charge of bee culture. 

D. M. Rogers, in charge of preventing spread of moths, field work. 
Rolla P. Currie, in charge of editorial work. 
Mabel Colcord, in charge of library. 

Southern Field Crop Insect Investigations. 

W. D. Hunter, in charge. 

W. D. Pierce, J. D. Mitchell, G. D. Smith. E. A. McGregor, Harry Pinkus, 
B. R. Coad, G. N. Wolcott, W. A. Thomas. R. W. Moui and, C. E. Hester, 
engaged in cotton-boll weevil investigations. 

A. C. Morgan, G. A. Runner, S. E. Crumb, D. C. Parman, engaged in tobacco 
insect investigations. 

F. C. Bishopp, A. H. Jennings, H. P. Wood, W. Y. King, engaged in tick inves- 
tigations. 

T. E. Hollow ay, E. R. Barber, engaged in sugar cane insect investigations. 
J. L. Webb, engaged in rice insect investigations. 

R. A. Cooley, D. L. Van Dine, A. F. Conradi, C. C. Kiumkiiaar, collaborators. 
2 



ADDITIONAL COPIES of this publication 
-^A may be procure* from the Superintend- 
ent or Documents, Government Printing 
Office, Washington, D. C, at 15 cents per copy 



LETTER OF TRANSMITTAL 



United States Department of Agriculture, 

Bureau or Entomology, 

Washington, D. C, May 3, 1912. 

Sir: I have the honor to transmit herewith a manuscript entitled 

" The Principal Cactus Insects of the United States," prepared by 

Messrs. W. D. Hunter and J. D. Mitchell, of this bureau, and the late 

F. C. Pratt, who for many years was in the employ of the bureau. 

In the work of the Bureau of Plant Industry on the utilization of 

the prickly pear as a farm crop it became evident that insect injury 

in plantings was of considerable importance. This observation was 

made by Mr. David Griffiths. In 1907 he brought the matter to the 

attention of the Bureau of Entomology and the investigation upon 

which the present manuscript is based was begun. During the work 

the bureau has profited by the close cooperation of Mr. Griffiths^ and 

many of his observations are included in this report. 

I recommend that this manuscript be published as Bulletin No. 113 

of the Bureau of Entomology. 

Eespectfully, L. O. Howard, 

Chief of Bureau. 

Hon. James Wilson, 

Secretary of Agriculture. 

3 



CONTENTS 



Page. 

Introduction 9 

Historical statement regarding cactus insects 11 

Number and classification of cactus insects 12 

The principal insects injurious to Opuntia, in order of their importance 13 

Insects affecting the roots or stems 13 

Species of the genus Moneilema 13 

Description of the larva of Moneilema crussum 14 

A cutworm 15 

Coccidae 15 

Species attacking the joints externally 15 

Chelinidea vittigera Uhler 15 

Nature of injury 16 

Distribution 17 

Variations 17 

Life history, and description of stages 18 

The egg 18 

The nymphal stages 18 

Dimorphism 19 

Hibernation 19 

Chelinidea tabulata Westwood 19 

Chelinidea sp 20 

The control of Chelinidea vittigera and allied species 20 

Mimorista flavidissimalis Grote 20 

The adult 21 

The larva 21 

The pupa 21 

Seasonal history 21 

Damage 21 

Control 22 

Disonycha varicornis Horn 22 

Stylopidea picta Uhler 22 

The cottony cochineal insect (Dactylopius confusus Cockerell) 23 

Enemies 24 

Control 24 

Minor species attacking the joints externally 25 

Species attacking the joints internally 25 

Melitara junctolineella Hulst 25 

Diversity of habits 27 

Description of immature stages 27 

The larva 27 

The pupa 27 

Parasite 27 

Control 27 

5 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



Species attacking the joints internally — Continued. Page. 

Melitara dentata Grote 28 

Melitara prodenialis Walker 28 

Melitara fernaldialis Hulst 29 

Gerstxckeria porosa Le Conte 29 

Gerstxckeria nobilis Le Conte 30 

Gerstseckeria clathrata Le Conte 30 

Marmara opuntiella Busck 31 

Species injuring the blooms 32 

Species injuring the fruit 32 

Narnia pallidicornis Stal 32 

Descriptive 33 

Asphondylia opuntiee Felt 34 

Cornifrons elautalis Grote 35 

Allorhina mutabilis Gory 35 

Sixeonotus luteiceps Reuter 36 

Polistes spp 36 

Liotropis contaminatus Uhler 36 

Dyotopasta yumaella Kearfott 36 

Ozamia lucidalis Walker ' 36 

Plalynota rostrana Walker 36 

Scavengers 37 

Copestylum marginatum Say 37 

Hermetia spp 38 

Stictomyia longicornis Bigot 39 

List of the principal cactus insects of the United States 39 

Species which injure the plant 40 

Parasites or enemies of the injurious species 45 

Scavengers 47 

Species which merely frequent the flowers 49 

Species incidentally associated with the plant 50 

Bibliography of cactus insects 53 

Index 59 



ILLUSTRATIONS, 



Page. 
Plate I. Longicorn beetle, Moneilema crassum, an important enemy of the 

prickly pear 12 

II. Work of the longicorn beetle, Moneilema crassnm, on the cactus, 

Echinocereus sp 12 

III. Work of the moth, Mimorista flavidissimalis, on joint of Opuntia 20 

IV. Larvae of the flea-beetle, Disonycha varicornis, on Opuntia leptocaulis. 20 
V. Two important scale insects of the prickly pear: The cottony cochi- 
neal insect (Dactylopius confusus) and Diaspis echinocacti cacti 24 

VI. Joint of prickly pear showing work of Marmara opuntiella 32 

VII. Studies of cactus insects. Fig. 1. — Eggs of Melitara junctolineella on 
spines of Opuntia. Fig. 2. — Eggs of Chelinidea vittigera on spine 
of Opuntia. Fig. 3.— Eggs of Copestylum marginatum on Opuntia 

spines. Fig. 4. — Narnia pallidicornis 32 

TEXT FIGURES. 

Fig. 1. Chelinidea vittigera: Adult 16 

2. Chelonus laticinctus, parasite of Melitara dentata 28 

3. Gerstseckeria nobilis: Adult 30 

4. Marmara opuntiella: Adult, larva, eggs, and pupal case 31 

5. Opuntia fruit with puparia of Asphondylia opuntise 34 

6. Copestylum marginatum: Adult 37 

7. Hermetia chrysopila: Adult 38 

8. Stictomyia longicornis: Profile, head, and wing 39 

7 



THE PRINCIPAL CACTUS INSECTS OF THE UNITED STATES. 



INTRODUCTION. 

The cactus plants of the genus Opuntia are among the most strik- 
ing objects to be seen in semiarid and arid regions. These plants, 
which are extremely picturesque, are accorded a prominent place in 
the illustrations and literature of early surveys, undertaken by the 
War Department, 1 and, from a scientific standpoint, are of great 
interest because the}' have been found to have adapted themselves to 
existence in regions of small rainfall in many remarkable ways. The 
numerous insects associated with cactus plants are naturally of great 
interest. These insects have adjusted themselves to the general condi- 
tions in the regions in which the plants grow and have also adapted 
themselves to the structure and habits of the plants themselves. 
Moreover, cactus insects have always held special interest on account 
of the cochineal insect. The cultivation of this species, which is 
indigenous to America, caused the prickly pear to be transported to 
remote parts of the globe, where it has been planted for the purpose 
of furnishing food for the dye-producing insect. The industry of 
rearing the cochineal insect was for years a very important one. It 
furnished valuable dyes which are still utilized for special purposes. 
In the Canary Islands alone, in 187G, the exportation of cochineal 
amounted to over 5,000,000 pounds. It has been determined that the 
bodies of about 70,000 cochineal insects are required to make a pound 
of the dried product. This gives an indication of the extent of the 
industry in the Canary Islands, which did not, however, produce 
nearly all of the supply which entered into commerce. 

Except for the cochineal insect, the species feeding upon Opuntia 
have been until recently rather of scientific than of practical im- 
portance. In the early days, since it was necessary to cultivate the 
Opuntia plant as food for the cochineal insect, anj r species which 
injured the plant were of economic importance. In fact, the treatises 
on the cultivation of the cochineal contain directions about the control 
of various species which damaged the plant. With the decadence of 
the cochineal industry, the cactus plants became nuisances, except 

1 Pacific Railways Report, vol. 4, p. 37, 1856; U. S. and Mexican Boundary Survey, 
vol. 2, p. 35, 1859. 

9 



10 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

where the tunas were utilized as food. 1 They occupied land that could 
be used to advantage for valuable crops. In this way. in a few j^ears, 
the plant was changed in character from a valuable one to a weed. 
Incident to this change the insects feeding upon Opuntia assumed an 
entirely different character. Instead of being considered pests, they 
came to be looked upon as beneficial on account of their destruction 
of the weed. In fact, in South Africa and Australia the encourage- 
ment of the insect enemies of prickly pear has been proposed as a 
feasible means of reducing the number of plants. 

Within very recent years, at least in so far as the United States is 
concerned, there has been another revolution in regard to prickly 
pear. It has been recognized for many years in the southwestern por- 
tion of the United States that the plant furnished a supply of food 
for cattle during drought that frequently prevented the starvation of 
large herds. It was considered, however, that this was a rather poor 
return for the loss of large grazing areas on which the plants grew 
and which in normal seasons without the prickly pear would have 
furnished large amounts of forage. Some years ago Mr. David 
Griffiths, then of the Arizona Agricultural Experiment Station, 
began an investigation of the feeding value of prickly pear. It Avas 
soon found that the plant has a surprisingly high feeding value. 2 
The greatest practical difficulty in the use of the plant for forage 
was the spines, but it was found to be possible to eliminate this diffi- 
culty by singeing the plants or by running them through machines 
which chopped them into small pieces. It was also discovered by Mr. 
Griffiths, 3 whose more recent work has been done as an agent of the 
Bureau of Plant Industry of this department, that when prickly 
pear is planted it responds readily to cultivation. In fact it was 
found that artificial plantings of the pear with only meager cultiva- 
tion furnished a growth in three years that was fully as great as the 
growth under natural conditions in double that period. At this 
point, however, it became evident that the insects affecting the prickly 
pear would need to be taken into consideration. In fact it appeared 
in the experimental plantings of the Bureau of Plant Industry that 
the insect injury was one of the most important obstacles to the culti- 
vation of the prickly pear as a farm crop. In this way there has been 

1 In this discussion we consider the prickly pear as a crop planted on a large scale 
but do not overlook the fact that its fruit has been utilized as food for man from very 
ancient times and is still an important human food in large areas. There has been no 
revolution as regards the tuna as food for man. It has always been important. How- 
ever, the tunas are obtained from wild plants, or from those cultivated on a compara- 
tively small scale about houses, and thus represent a system of growth quite different 
from the extensive field culture of the early days. 

2 The Prickly Pear and other Cacti as Food for Stock, by David Griffiths. (Bui. 74, 
Bur. Plant Ind., U. S. Dept. Agr., March 8, 100",.) Feeding Prickly Pear to Stock in 
Texas, by David Griffiths. (Bui. 01, Bur. Plant Ind., U. S. Dept. Agr., 1906.) 

3 Prickly Pear as a Farm Crop, by David Griffiths. (Bui. 124, Bur. Plant Ind., U. S. 
Dept. Agr., February 19, 1908.) The Tuna as Food for Man, by David Griffiths and B. F. 
Hare. (Bui. 116, Bur. Plant Ind., U. S. Dept. Agr., December 2, 1907.) 



HISTORICAL STATEMENT. 11 

a complete revolution in so far as the importance of cactus insects is 
concerned. 

HISTORICAL STATEMENT REGARDING CACTUS INSECTS. 

It has been stated in a preceding paragraph that the insect enemies 
of Opuntia attracted some attention in former years on account of 
their injury to the host plant of the cochineal insect. Several of the 
treatises on the cultivation of the cochineal contain brief suggestions 
about the destruction of the enemies of the plant, as well as about 
the enemies of the cochineal itself. In all these considerations, how- 
ever, only the merest incidental attention was paid to species other 
than the cochineal. 

The first systematic work on cactus insects that was undertaken 
was that done in 1895 by Mr. H. G. Hubbard, who lived in Florida. 
He discovered a lepidopterous larva, Melita/ra prodenialis Walk., 
which feeds upon the prickly pear, traced out its life history and 
transformations, and published a most interesting account of his 
observations. 1 A few years later Mr. Hubbard sojourned for some 
months in Arizona. In that territory he made studies of the insect 
fauna of the giant cactus (Cereus giganteus). Although plants of 
the genus Cereus will probably never be of importance as forage, 2 
Mr. Hubbard's studies have a bearing upon insects infesting Opuntia, 
since the faunas of Cereus and Opuntia are largely the same. After 
his death, the results of Mr. Hubbard's investigations were published 
under the editorship of Mr. E. A. Schwarz. 3 

From 189G to 1898, on various trips to the region then infested by 
the boll weevil, Mr. E. A. Schwarz made a number of observations 
on insects infesting Opuntia. In fact, he discovered a number of the 
species which have now been found to be of importance in the area 
in which the prickly pear is undergoing cultivation. Dr. L. O. 
Howard and Mr. C. L. Marlatt also made observations on cactus 
insects at about this time. The results of these incidental observa- 
tions were published in notes in the Proceedings of the Entomological 
Society of Washington. 

By 1905 Mr. David Griffiths had begun the cultivation of the 
prickly pear in the vicinity of San Antonio, Tex., and elsewhere. It 
was on his experimental plantings that the observation was made 
that the concentration of the plants under cultivation seemed to 
increase the amount of insect injury. Recognizing the importance 
of this matter, Mr. Griffiths immediately began the collection of 
specimens which, with full notes, were transmitted to the Bureau 

1 rroc. Ent. Sue. Washington, vol. ::. pp. 129-1.°,2. two figs., 1895. 

2 The Cereus plants are, of course, utilized in many ways by the inhabitants of the 
region in which they occur, but not as forage. 

3 Psyche, May, 1899, Supplement, pp. 1-14. 



12 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

of Entomology at Washington. This material was placed in the 
hands of Mr. E. S. G. Titus and Mr. F. D. Couden. In spite of the 
difficulties of rearing the specimens, due to the transportation to 
Washington and the utterly different climatic conditions, these ento- 
mologists succeeded in rearing a large number of specimens. This 
material, with the rearing notes and the field notes supplied by 
Mr. Griffiths, has been used in the preparation of this bulletin. 

In 1D07 Mr. Griffiths' field observations mgre than verified his 
previous impressions regarding the importance of cactus insects. 
By this time it had also become evident that the rearing work could 
be carried on to much better advantage in the regions where the 
Opuntia was grown and that field experiments in control were neces- 
sary. For these reasons, in 1907 the investigation was turned over 
to the branch of Southern Field Crop Insect Investigations. In con- 
nection with other work Mr. F. C. Pratt and Mr. J. D. Mitchell were 
detailed to institute an investigation of cactus insects in Texas. Mr. 
Pratt's work was continued with serious interruptions, due to his 
ill health, from late in 1907 until the fall of 1910. During this time 
he and Mr. Mitchell accumulated a very large amount of information 
about the insects associated with the Opuntia plant and regarding 
feasible means of control of the more injurious species. The origi- 
nal intention was that a publication on this subject should be pre- 
pared by Mr. Pratt. His ill health, which became acute about the 
time that sufficient material had been gathered to form the basis of a 
bulletin, and his death soon afterwards, prevented placing the matter 
in form for publication. This part of the work has been done by 
the senior author, who has also made some field observations, although 
the great majority of such observations were made personally by Mr. 
Pratt and Mr. Mitchell. 

NUMBER AND CLASSIFICATION OF CACTUS INSECTS. 

As the result of the work we have done and that of the previous 
investigators who have been mentioned, 324 species of insects are 
known to be associated with the cactus plant. These divide them- 
selves naturally into five categories, as follows: Species injuring the 
plant, 92; parasites of injurious species, 28; scavengers, 73; flower 
visitors, 40; species only incidentally associated with the plant, 91. 

The injurious species affect different, parts of the plant. In fact, 
no important part of the plant is immune from injury. Twelve 
species are known to attack the roots or stem. Twenty-seven species 
attack the joints, of which 11 species feed inside of the joints 
while 16 destroy the outer portion. A considerable number are 
found in the blooms; a few of these are injurious, but others undoubt- 
edly assist in the fertilization of the plant. The fruit is injured by 

13 species. 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate I. 




Longicorn Beetle, Moneilema crassum, an Important Enemy of Prickly Pear. 

Adults feed on exterior of joints of the cactus, while the larvae destroy the interiorof both 

joints and stems. Enlarged. (Original.) 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate II. 




Work of Longicorn Beetle, Moneilema crassum, on the 
Cactus, Echinocereus sp. (Original.) 



INSECTS AFFECTING THE BOOTS OR STEMS. 13 

The foregoing arrangement of five categories will be followed in 
the body of this bulletin. Within these categories the species will 
be treated in the order of their importance. In this place, however, 
we shall include a list of the principal species arranged as they rank 
in importance regardless of the parts of the plant affected. 

THE PRINCIPAL INSECTS INJURIOUS TO OPUNTIA IN ORDER OF 
THEIR IMPORTANCE. 

1. Chelinidea, 3 species. Feeding upon the joints externally. 

2. Mimorista flaridlssi mails Grote. Attacking joints externally 
at first but later invading inner portion. 

3. Narnia, 4 species. Feeding on joints externally. 

4. Melitara, 4 species. Feeding within the joints. 

5. Moneilema, 8 species. Feeding within joints and stems. 

6. Dactylopius confusus Cockerell and D. tomentosus Lamarck. 
Feeding on surface of joints. 

7. Marmara opuntiella Busck. Forming mines beneath surface of 
joints. 

8. Asphondylia, 3 species. Feeding on interior of fruit. 

9. Stylopidea picta Uhler. Feeding on surface of joints. 

10. Diaspis echinocacti cacti Comstock. Feeding on surface of 
joints. 

11. Ozaonia lucidalis Walker. Infesting the fruit. 

12. Platynota rostrana Walker. Feeding within the fruit. 

13. Polistes, 3 species. Feeding on the fruit. 

INSECTS AFFECTING THE ROOTS OR STEMS. 
Species of the ,Genus Moneilema. 

Among the insects which affect the roots or stems the most impor- 
tant forms are eight species of the cerambycid genus Moneilema, to 
which the common name "Opuntia longicorns " may be applied. 
These are wingless, robust, shining black beetles, 1 from about 15 to 
25 mm. in length. (See PL I.) They are to be found upon the 
Opuntia plants as adults throughout the season. In the adult stage 
they do considerable injury by gnawing the edges of the neAvly 
formed joints. This injury, however, is insignificant in comparison 
with that done to the stems and roots by the larvae. 

The most important species of Moneilema in Texas are M. crassum 
Le Conte and M. ulhel Horn. These are widely distributed in the 
State. Other species are included in the list at the end of this bul- 
letin. 

It is interesting to note that the work of the adult beetle sometimes 
results in the dissemination of the plant. Frequently the beetles cut 

1 One species, ulkei, is opaque, its surface mottled with whitish. 



14 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

at the base of a newly-formed joint, so that it is soon broken from 
the plant. In some cases the joints thus separated from the plants 
take root upon falling to the ground. As a matter of fact this acci- 
dental planting by the Moneilema beetles is one important cause for 
the growth of the prickly pear in very dense clusters around the old 
plant. 

DESCRIPTION OF THE LARVA OF MONEILEMA CRASSUM. 1 

About 12 mm. long when full grown. Body white, with a dark-brown chitin- 
ous head and with a pale-yellow semichitinous prothoraeic area. Head trans- 
verse, rounded oblong, with the labrum, sometimes the labium, and the maxilla? 
light yellow in contrast to the dark-brown mandibles and occiput. Eyes ob- 
scured. Antenna? single jointed, very small, placed immediately behind the 
mandibles. Labrum and clypeus transverse; mandibles large, apically emargi- 
nate, distant ; maxillary and labial palpi small. Body sparsely covered with 
brown setae. Prothorax tumid, twice as large as either mesothorax or meta- 
thorax. Mesothoracic spiracles plain. Abdomen 10-segmented, the last 2 modi- 
fied, forming the anal region; first 8 segments provided with large, round 
spiracles; first 6 dorsally prominently bituberculate; first 7 ventrally trans- 
versely grooved. 

These larva? infest the main stem and older joints of the prickly 
pear. The gallery is wide and soon becomes blackened. The frass 
frequently becomes infested with dipterous larva? of various species. 
The larva? are capable of considerable movement and have been found 
frequently to travel from one part of the plant to another in order 
to obtain a better supply of food. After attack the plant appears 
sickly and shows copious exudations of black sap which becomes so 
hard that it can be cut with a knife with great difficulty. The ap- 
pearance of this black exudation is shown in an accompanying illus- 
tration (PI. IT). 

The larva makes an imperfect cocoon, in which transformation to 
the pupa takes places. These cocoons consist of an inner layer of fiber 
of the cactus plant covered with sand. The texture is very firm. 
They measure 25 by 35 mm. They are generally found just beneath 
the prostrate joints on the ground. The duration of the immature 
stages was not determined, but it is evident that there is only one 
generation during the season. Adults appear most commonly in 
April and May and in September. 

As the Moneilema beetles are among the more important insects of 
the prickly pear, it may be necessary to combat them in plantings. 
Three means of attack are in evidence from the account that has just 
been given, namely, burning, hand picking, and poisoning. The 
larva? and cocoons can be destroyed by burning the prostrate portions 
of the plants. The injury can always be located by reason of the 
large number of joints and stems that have fallen to the ground. A 

1 Prepared by Mr. W. D. Pierce. 



SPECIES ATTACKING JOINTS EXTERNALLY. 15 

little work in raking togetner and burning the fallen portions of the 
plant where they are numerous would serve to hold the insect in 
check. If this practice has not been followed, it will still be possible 
to check injury with some satisfaction either by poisoning the adults 
or by collecting them by hand. On account of their large size and 
sluggish movements and the fact that they are without wings, hand 
collecting is not difficult and will be very effective. This process 
would generally be preferred to that of poisoning on account of its 
cheapness. When poisoning is practiced, arsenate of lead should be 
used. It should be applied, in powdered form only, to the young and 
tender joints, as the adults feed upon no other parts of the plant. 
The poisoning of these young joints will also serve to control at least 
one other important enemy of Opuntia, as will be described later. 

A Cutworm. 

On several occasions a cutworm. Chorlzagroth soror Smith, has 
been found to do considerable injury to Opuntia plants. The damage 
is greatest in the case of young plantings. The pulp that is exposed 
in cutting the joints into suitable pieces for planting seems to attract 
these worms. In one of the plantings at San Antonio, Tex., they ate 
canals through the underground portions of the plants. They are 
partial to the varieties of more tender structure. "Whenever this in- 
sect is abundant it will be easy to protect the plants by soaking the 
portions used for seed for a few minutes in a solution of arsenate of 
lead, or, if more convenient, the sections to be planted could be dusted 
with the powdered arsenate of lead at the time of planting. 

Coccidae 

The only other insects which have been found attacking the roots 
of Opuntia plants are three species of Coccidae, or scale insects. 
None of these species has been found to be abundant or to have any 
marked effect upon the vigor of the plant in the localities in which 
they occur. It is consequently unnecessary to give them further 
attention. 

SPECIES ATTACKING THE JOINTS EXTERNALLY. 

Chelinidea •vittigera Uhler. 1 

The coreid bug, Chelinidea vittigera Uhler, may be readily recog- 
nized from the following brief summary of its appearance and 
habits: 

It is a yellowish bug resembling the common squash bug (Anasa 
tristis De Geer) in general appearance (fig. 1), about 15 mm. long, 

1 Order Hemiptera, Family Coreidse. 



16 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 







feeding generally gregariously on the joints of Opuntia and allied 
genera. It is chiefly nocturnal in its habits. The first indications 
of feeding are the occurrence of lighter circular spots on the joints. 
The whitish excrement of the insect, which covers the surface of the 
joint, is also conspicuous. During the winter the insects are to be 
found in large numbers in a somewhat dormant condition under pros- 
trate joints. 

This species and its congeners are restricted to cactus plants and 
are by far the most important Opuntia insects occurring in the 
United States. On account of the wide distribution and prolific 
breeding of C. vittigera it is conspicuous in all localities where it 
occurs. Within its range Mimorista flavidissimalis Grote is proba- 
bly more destructive to the plants, but that species is restricted to 

a comparatively small portion of 
the area occupied by Opuntia. 

NATURE OF INJURY. 

The small circular discolora- 
tions on the joints resulting from 
the work of this insect do not 
appear until feeding has pro- 
gressed for some time. As soon 
as they do make their appear- 
ance, however, they are extremely 
conspicuous. They may be found 
upon only a few joints of a plant, 
or where the bugs are more abun- 
dant all the joints may be affected. 
As the injury proceeds, the spots 
become larger and coalesce, so that the whole area of the epidermis 
assumes a deadened, yellowish, and pitted appearance. The whitish 
excrement is discharged more profusely when the bugs are approached 
and may possibly have some protective effect. 

As a result of attack the plant is weakened so that it soon falls 
over. Where the bugs are numerous the fallen plants give somewhat 
the same appearance as they would if battered down by heavy hail. 
In some cases, where the attack is not strong, portions of the fallen 
joints take root and give rise to new plants. More frequently, how- 
ever, the joints are unable to recuperate and either dry up completely 
or become the breeding places for the mam^ species of scavenger 
insects found associated with the cactus plant. 

As soon as the bugs, whether in the nymphal or adult stages, have 
weakened a plant they migrate to other plants and continue the work 
of destruction. 




Fig. 1. — A cactus insect, Chelinidea vit 
tigera: Adult. Enlarged. (Original.) 



SPECIES ATTACKING JOINTS EXTERNALLY. 17 

It has been observed by Mr. J. D. Mitchell that the joints upon 
which the bugs have fed, and which may not have shown any special 
damage during the season, are the ones first injured by frosts during 
the following winter. This indirect injury sometimes results in set- 
ting the plants back by as much as the growth of two years. Another 
form of injury which is suspected but not proven in the case of this 
bug is the dissemination of the fungous disease Perisporium sp. This 
disease causes large black spots on the joints. The infected area fre- 
quently drops out, leaving a more or less circular opening through 
the joint. The feeding habits of the bug are such as to render it very 
likely to plant the spores of the fungus when it travels from one 
joint to another. 

This species was first called to attention as an enemy of Opuntia 
by Mr. F. W. Thurow, who, in March, 1893, reported to the Depart- 
ment of Agriculture that. three species of Opuntia growing in Harris 
County, Tex., were greatly damaged. 1 

DISTRIBUTION. 

This species is not confined to the prickly-pear region 'proper, 
although there is no doubt that it greatly prefers that plant and 
that it is much more abundant where the Opuntia occurs in large 
numbers. Its western limit in Texas, so far as ascertained, is Brews- 
ter County. In the east it occurs along the Gulf and inland as far as 
Trinity County, Tex. It has been taken in Dallas and Parker 
Counties, Tex., wherever Opuntia occurs. It has also been observed 
in California, Utah, and Colorado, and in fact is generally distrib- 
uted throughout the Western and Southern States. In the East it is 
found in Louisiana, Alabama, and North Carolina and has been 
recorded from Virginia. 

VARIATIONS. 

The following notes on variations in Chelinidea vittigera have 
been furnished by Mr. O. Heidemann, who examined all of the 
hemipterous insects taken on cactus: 

The species is exceedingly variable in structure of the body and in color. 
The relative length of the head, described by Prof. Uhler as being two-thirds 
the length of the thorax, can hnrdly be considered as a constant character. 
There are specimens which have the head and thorax subequal in length or 
equal. The peculiar prism-shaped antennal joints are more or less dilated, 
in some examples very conspicuously. This variation in the dilatation of the 
antennal joints is noticeable even in those specimens marked as reared from 
Opuntia. The color of the antennae, elytra, and legs varies considerably, chang- 
ing from reddish-brown into black. The darkest, most developed forms occur 
in Colorado and Utah. 

1 Insect Life, vol. 5, p. 345. 
50975°— Bull. 113—12 2 



18 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

LIFE HISTORY, ANE) DESCRIPTION OF STAGES. 

The oreeding of this insect in the cactus area begins early in the 
season. At San Diego, Tex., in March, Mr. J. D. Mitchell observed 
that the first brood had appeared. In April the first young were 
noticed in Victoria County. The bugs breed continuously throughout 
the summer and fall. Owing to the fact that certain individuals are 
retarded in their development no definite number of broods is deter- 
minable. It has frequently been observed that some specimens reach 
the adult stage before others from the same mass of eggs have passed 
the third nymphal stage. This explains the observation of many per- 
sons that the bugs can be found in all stages on the plants at all times 
except during cold weather. 

The eggs are deposited generally on the spines, although in confine- 
ment the females deposit on the sides of rearing cages and in some 
instances eggs have been observed on the sides of dead as well as of 
living joints. The spines, however, are undoubtedly the normal place 
for deposition of the eggs. (See PI. VII, fig. 2.) During the summer 
season 5 adults produced 198 eggs in 15 days, averaging practically 
40 to the individual. These females were not reared, so that it is more 
than likely that the capacity for egg laying is much larger than the 
figures would indicate. The method of oviposition was observed by 
Mr. C. E. Hood. He noted that the female begins by rubbing the 
spines or surface on which the eggs are to be laid with the tip of the 
abdomen, probably discharging a sticky substance. After the egg is 
about halfway protruded a circular motion of the abdomen is ob- 
served. The female then appears to rub the egg over the spine before 
finally discharging it. In this manner 4 eggs were deposited in 6 
minutes. It was observed in the breeding cages, and frequently in 
the field, that the eggs are not securely fastened to the spines. The 
attachment is so weak that they fall as the result of even a slight 

disturbance. 

The Egg. 

Length, 1.25 nun. ; width, 0.75 mm. Dark brown, opaque, very finely and 
uniformly punctured, mottled with a whitish exudation. Elliptical; lid sub- 
dorsal, large elliptical. Placed with great regularity about 0.5 mm. apart on 
spines, with longitudinal axis parallel to spine, each string of eggs from 6 to 25 
mm. in length. Duration of egg period, from 12 to 20 days. 

The Nymphal Stages. 

First instar. — Length, 2 mm. Brownish black, except abdomen, which is pea- 
green in some individuals and a dark crimson in others. The former variety 
shows a slightly red callosity and margins. Antenna? 4-jointed ; club short ; 
first joint slightly flabellate; second joint scarcely one-third longer than the 
third ; first and second joints with apical tips terminating in short spine. Head 
produced, bifurcate. Length of stage, 7 days. 



SPECIES ATTACKING JOINTS EXTERNALLY. 19 

Second instar. — Length, 4 rum. Very little change from first instar except 
that the femora and prothorax have a slightly lighter color. Second joint of 
antenna with almost straight sides. Spines on first and second joints more pro- 
nounced. Length of stage, 4 days. 

Third instar. — Length, 5.5 mm. Spines on first and second antennal joints 
slightly more pronounced, as is the raised callosity on the abdomen. The two 
transverse brown slits very conspicuous. Prothorax changing to greenish. 
Antennae inore distinctly flabellate; otherwise there is little change. Length of 
stage, 4 days. 

Fourth instar. — Length, 6.5 mm. Greenish color on abdomen decidedly 
darker; legs, antennae, head, and thoracic spines olivaceous black. No change 
in spines. Length of stage, 12 days. 

Fifth instar. — Length, 7.5 mm. The abbreviated wing-pads appear and ex- 
tend over the two anterior abdominal segments. General color dull olivaceous 
black, except tips of antennae, which are orange. Prothorax considerably wider, 
thus altering the appearance greatly, as the previous stages have a very narrow 
prothorax in comparison to the abdomen. Length of stage, 14 days. 

The duration of the fourth and fifth instars was determined during 
October; that of the earlier stages in July and August. Un- 
doubtedly the duration of the last stages in summer does not greatly 
exceed that of the earlier ones. 

DIMORPHISM. 

In the examination of several thousand of these bugs which have 
been under observation- in the field and in rearing cages it was 
noticed that there was a great variation in the color of the adults 
from different localities. This variation is much more noticeable in 
the nymphal stages. The color of the abdomen is either pea-green 
or dark crimson. Repeatedly experiments in breeding these color va- 
riations resulted in rearing adults which could not be distinguished. 

HIBERNATION. 

At a temperature from 45° to 50° F. these bugs appear to be rest- 
less, congregating at times, and at other times dispersing in order 
to find suitable quarters for hibernation. Throughout the winter 
they are to be found in numbers under fallen cactus joints, in the 
trash that accumulates at the base of the plants, under grass roots, 
and in fact wherever they can obtain shelter in the immediate 
vicinity of the Opuntia. They do not seem to travel any consider- 
able distances from the plant upon which they were produced. 

Chelinidea tabulata Westwood 

The species Chelinidea tabulata Westwood has often been observed 
in company with Chelinidea vittigera. It is not common, but if it 
were it would easily rank as a pest of prime importance on Opuntia. 
It is a Mexican species hitherto not known to occur in the United 
States. In our collections it has been taken at many localities from 
Austin, Tex., southward and westward. 



20 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Chelinidea sp. 

A third species of the genus Chelinidea was taken in May at 
Tuscon, Ariz., on Opimtia arbuscula, O. versicolor, and 0. fulgida. 
This species is somewhat smaller than the preceding. Rearing ex- 
periments were unsuccessful on account of the shipment of the species 
into a region of different climate. 

The Control of Chelinidea vittigera and Allied Species. 

Two features of the life history of these bugs reveal feasible means 
of control. These are the clustering of the adults during winter and 
the gregarious habits of the young. The best control practice to 
follow is undoubtedly to collect and burn the trash on which the 
insects are found during the winter. At that time they are almost 
completely dormant and can be raked into piles along with the 
debris and burned. The gregarious habit, which is especially well 
marked in the earlier immature stages, makes it easy to check the 
development in a different way. The use of the gasoline torch, which 
is found upon all plantations where the cactus is used for forage, 
gives an economical and effective method of destroying these stages. 
Whenever the appearance of the small circular spot and of the white 
excrement shows that the insects are beginning to injure the plants 
seriously, the torch can be brought into play to excellent advantage. 

Mimorista flavidissimalis Grote. 1 

The cactus insect Mimorista, flavidissimalis Grote may be rec- 
ognized easily from the following description: 

From one to seven yellowish larvae feeding invariably on upper 
edge of young joints of Opuntia under a silken web, sometimes pene- 
trating the interior. (PI. III.) 

After the Chelinidea bugs, this insect is the most important enemy 
of Opuntia in the United States. Unlike the Chelinideas, however, 
it is restricted in its range. In Texas it is found from Hallettsville 
and San Antonio southward. West of San Antonio it is rare, but 
was taken at Tucson, Ariz., in May by Mr. Pratt. In the area where 
it is common it is by far the most injurious cactus insect. 

The species was described by Grote in 1877 from specimens re- 
ceived from Texas. Since then it has not been recorded outside of 
Texas. It was not until 1905, when the present work was under- 
taken, that anything was known about the early stages. The first 
rearings were made at Washington, D. C, from material collected 
at San Antonio, Tex., by Mr. David Griffiths. 

1 Order Lepidoptera, family Pyralidae. 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate III. 




w 






Work of Moth. Mimorista flavidissimalis, on Joint of Opuntia. (Original.) 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IV. 




Larv/e of Beetle, Disonycha varicornis, on Opuntia leptocaulis. 

• Original.) 



SPECIES ATTACKING JOINTS EXTERNALLY. 21 

THE ADULT. 

The adult is a ruoth which expands about 1 inch. It is bright straw colored, 
with inconspicuous brownish markings arranged in four irregular transverse 
bands. 

THE LARVA. 

Length, 11 mm. ; shining ; general color yellowish white ; legs concolorous ; head 
and cervical shield somewhat darker yellow. Sides parallel, except for slightly 
raised spiracular callosities; faintly impressed median line. Two minute spots 
on cervical shield and spiracles black. Hairs long, sparse; most numerous on 
first six segmeuts; white in color; arranged in subdorsal, marginal, and sub- 
marginal series ; none on median line. 

THE PUPA. 

Inclosed in a whitish cocoon of thin, dense, paper-like construction ; length, 
9 mm. ; width, 3 mm. ; shining, light brown ; head black. On thoracic segment 
one median and eight lateral fine longitudinal dai'k lines ; the ones on either 
side of the median line ai*e double for a short distance near their anterior third. 

SEASONAL HISTORY. 

A generation of this species is produced in about 30 days. The 
earliest record of the rearing was made by Mr. J. D. Mitchell on 
May 29 at Victoria, Tex. In that locality the second generation of 
the year had developed by June 26. The fifth generation matured 
by September 15. In all probability there is one additional brood 
during the season in southern Texas. 

DAMAGE. 

The injury by this species is confined to the young joints. Mr. 
Mitchell has repeatedly seen from 50 to 75 per cent of the new growth 
destroyed over considerable areas. The moth deposits from one to 
seven eggs, always on the upper edge of the joint. The first indi- 
cations of injury are strings of sap exuding from the joints. If this 
discharge is removed a small hole becomes visible. As the larvae 
develop the discharge of sap from the plants becomes mixed with 
silk, trash, and excrement discharged by the insects. (PI. III.) 
In rare cases, when only a few eggs have been deposited, the joint 
recovers, although it is always deformed. In most instances, how- 
ever, decay begins, and the joint turns black and finally drops to the 
ground. 

The two features of the attack of this insect which cause it to be 
of great importance in connection with the cultivation of cactus are, 
first, the large number of broods occurring throughout the season, 
and, second, the attack against the new growth. Where the species 
is at all abundant this attack effectually prevents any additional 



22 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

growth of the plants. At the end of the season there are no more 
joints than there were the year before. 

A hymenopterous parasite of this species, Eiphosoma texana Cres- 
son, has been reared. It does not appear, however, to be sufficiently 
abundant to exert much control over the species. 

CONTROL. 

Mr. J. D. Mitchell has found by experiments performed at Vic- 
toria, Tex., that it is not difficult to control the species by the early 
application of powdered arsenate of lead. As soon as damage be- 
comes evident in the spring the new growth should be dusted care- 
fully with this arsenical. In this way the majority of the first 
brood will be destro} r ed. Some of the joints infested at that time will 
recover and there will be little injury from the following broods. 
The early application of the arsenical is very important on account 
of the formation of the protective web soon after the larvse have 
begun work. If the first brood should not be reached in time every 
effort should be made toward applying the poison in ample time for 
the second brood. 

In the case of small experimental plantings the use of the gasoline 

torch will furnish an economical means of control. In other cases 

the cutting off and burning of the early infested joints will answer 

the same purpose. 

Disonycha varicornis Horn. 1 

Disonycha varicornis Horn is a flea-beetle about 7 mm. in length. 
It is of conspicuous appearance on account of the brilliant polished 
blue of the elytra. The head and thorax are yellow; the under parts 
dark brown. So far as known this insect is restricted to Opuntia 
leptocaulis and Opuntia arborescens. It has never been found on the 
broad-leafed species of the genus Opuntia. It is observed frequently 
on its host plants in the adult and immature stages. The larvae feed 
on the surface of the plants without any protective covering what- 
ever. (PI. IV.) Frequently they occur in such numbers as to cause 
the death of the plants. As it happens that the cacti attacked by this 
insect are not of any special economic importance, it is unnecessary to 
give further attention to the species. 

Stylopidea picta Uhler. 2 

Stylopidea picta Uhler is a slender hemipterous insect about 6.5 
mm. long. The head and thorax are bright crimson and the wing 
covers slate color but with narrow yellowish borders. The eyes are 

1 Order Coleoptera, Family Chrysomelidoe, Subfamily Halticinse. 
- Order Hemiptera, Family Capsidse. 



SPECIES ATTACKING JOINTS EXTEENALLY. 23 

placed at the end of the stalk-like prolongations of the head. The 
under parts are dark brownish. 

The species has been collected on Opuntia from San Antonio, Tex., 
to the coast and southward to Brownsville, Tex. It seems to be more 
abundant in the vicinity of Corpus Christi, Tex., than elsewhere. 
The injury is not conspicuous. It causes the plants to assume a 
spotted appearance, but, except where the bugs are unusually abun- 
dant, the joints recover. It is not a true cactus insect, but has been 
found upon a variety of other plants. On account of its gregarious 
habits it could be easily controlled by means of the gasoline torch 
when it becomes unusually abundant. 

The Cottony Cochineal Insect. 1 
(Dactylopius confusus Cockerell.) 

The cottony cochineal insect {Dactylopius confusus Cockerell) is 
easily recognized by the large flocculent masses of pure white wax 
which covers the bodies. (PI. V, upper figure.) When crushed 
the bright crimson color of the body fluid runs out and contrasts 
strongly with the white envelope. These scale insects are found on 
the joints of Opuntia. frequently in large masses. 

This species is closely allied to the true cochineal insect, Dactylo- 
pius coccus Costa, which does not appear to occur in the United 
States. 2 The true cochineal has only a light powdery covering, while 
the form in the United States is provided with the heavy covering of 
cottony wax which has been described. 

The true cochineal insect has had a most interesting history. Car- 
ried to many parts of the world and cultivated with extreme care, 
for many years the dried bodies of the females yielded a dye product 
of great importance in the commercial world. It was also supposed 
to be an important therapeutic agent. 

In A. von Humboldt's Political History of the Kingdom of New 
Spain, published in 1811, there is a most interesting account of the 
cochineal industry in southern Mexico. The author relates that there 
was every indication that the cultivation of the insect had been prac- 
ticed for many centuries, undoubtedly, even antedating the invasion 
of the Toltec tribes. During the reign of the Aztec kings the in- 
dustry was apparently much more important than at the time of 
Humboldt's observations. As early as 1592 laws were passed to pre- 
vent the adulteration of the product. In 1802 the exports through 
the port of Vera Cruz amounted to 3,308,557 pounds. 

The greatest development of the cochineal industry occurred about 
1870. The decline began at that time on account of the discovery 

1 Order Hemiptera, Family Coceida\ 

2 The records from Florida nod California in Ihe Fernald Catalogue are probably due to 
importations. 



24 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

of aniline dyes. For several years the commercial cochineal crop of 
the world amounted to more than 7,000,000 pounds. Although the 
amount produced now is very much smaller, it seems to be more or less 
constant. In 1909, the last year for which statistics are available, the 
United States imported 102,000 pounds of a value of $33,875. Prac- 
tically all of this supply is obtained, either directly or indirectly, 
from the Canary Islands. The average annual importation into the 
United States for seven years ending with 1909 was 130,000 pounds. 

Cochineal is now used as a coloring matter for fine fabrics, certain 
kinds of ink, and confectionery. It is also used as a coloring medium 
for solutions and emulsions, being found practically in every drug 
store in the country. For many years it was used more or less regu- 
larly as an anodyne, but this use has been largely discontinued. 

The cottony cochineal insect occurs practically throughout the 
cactus region in the United States. It has been found to be abundant 
as far north as Young County, Tex. It is attacked by a large num- 
ber of predaceous insects. These tend greatly to hold the cochineal 
insect in check. Otherwise it would be a pest of prime importance 
on Opuntia plantations. As it is, it not infrequently becomes so 
abundant as to destroy portions of the plants and, on occasions, even 
as far north as central Texas, it has been found that entire plants 
have been destroyed. 

ENEMIES. 

The insect enemies of the cottony cochineal insect, so far as known, 

consist of eight species of Coleoptera and three of Lepidoptera, as 

follows : 

Coleoptera. 

Exochomvs latiusculus Casey; Exochomvs marginipennis Le Conte; 
Cycloneda munda Say ; CMlocorus cacti Linnaaus ; Hyperaspis trifur- 
cata Schaeffer; Hyperaspis omenta Le Conte; Scymnus loewii Mul- 
sant ; Scymnus hornii Gorham. 

Lepidoptera. 

Lcetilia coccidivora Comstock; Zophodia dilatifasciella Ragonot; 
Solaria ardiferella Hulst. 

CONTROL. 

Attention has been called to the fact that in the United States the 
insect enemies of the cottony cochineal insect prevent its reaching 
great numbers until the middle of summer. In artificial plantings at 
times it may be necessary to resort to remedial work. In such cases 
the best plan to follow will be to remove the masses on the joints 
by means of a very stiff brush or to burn them with a torch. In some 
cases spraying with kerosene emulsion or the lime-sulphur mixture 
might be followed, but the extensive secretion of the insect will 
interfere greatly with the application of any insecticides. 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agricultu 




Two Important Scale Insects of Prickly Pear. 

Upper figure, the cottony cochineal insect, Dactylopius cortfusus; lower figure, l>in.<i>i.< cchinocacti 
cacti. Lower figure enlarged. (Original.) 



SPECIES ATTACKING JOINTS INTERNALLY. 25 

In hothouses the use of a solution of whale-oil soap or of tobacco 
stems is recommended for this and other scale insects of cacti. Any 
preparation that may be used should be applied with considerable 
force by means of a spray pump in order to reach the insects in the 
crevices of the plants. 

Minor Species Attacking the Joints Externally. 

In addition to the species described in the preceding pages a con- 
siderable number of forms have been found which occasionally feed 
upon the joints. None of the other forms is at present known to be 
of any great economic importance, although they are likely to become 
abundant and injure the plants under local conditions at any time. 
The species more likely to do so are mentioned in the following 
paragraph. 

Diaspis echinocacti cacti Comstock is a grayish scale insect, the 
females circular and the males oblong. It sometimes becomes so 
numerous as to cover entirely the surface of the joint. This con- 
dition is shown in an accompanying illustration. (PL V, lower 
figure.) In artificial plantings and in hothouses this species is of 
some importance. Under field conditions it rarely reaches excessive 
numbers. Dactylojnus tomentosus Lamarck, which resembles the 
cottony cochineal insect but differs from that species by the fact that 
the separate individuals, instead of masses of several individuals, are 
covered by the cottony secretion, may be destroyed by the means 
recommended for the cottony cochineal insect. The white ant Tennes 
flavipes Kollar feeds upon a great variety of cactus plants and has 
been observed to injure the joints thrown on the ground for growing 
a new crop. It sometimes constructs nests in the damaged joints. 
The scale insect Eriococcus coccineus Cockerell has been recorded 
from California. Aphis medicaginis Koch, a plant louse, apparently 
passes the winter on Opuntia in Texas. During the remainder of 
the year it is seldom found on Opuntia plants, and on the whole 
causes only very slight injury. 

SPECIES ATTACKING THE JOINTS INTERNALLY. 

Melitara junctolineella Hulst. 1 

Melitara junctolineella Hulst and the other species of the genus 
are true cactus insects. They may be recognized from the following 
brief description: Large indigo-blue (young) or conspicuously 
banded (last stage) larvae living within the joints of Opuntia, cause 
large excavations and tumor-like swellings of the infested joints. 
The adult is a grayish moth of an expanse of 1^ inches. 

The eggs of this species are very similar to those of Melitara pro- 
denialis Walk, which are described on another page. They are 
deposited in exactly the same manner. The remarkable arrangement 

1 Order Lepidoptera, family Pyralidae. 



26 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

is shown in one of the accompanying photographs. (PI. VII, fig. 1.) 
The individual egg masses may contain as many as 30 eggs. 

There seems to be only one brood each year. As soon as the larvae 
hatch in the spring they begin feeding upon the surface of the joint. 
Within a few days they make their way to the inside and never 
appear upon the surface. The experience of all observers is that only 
one or two larvae are ever found within a joint. This is remarkable 
in view of the fact that the eggs are deposited in such numbers. 
Apparently it is not a case of the young larvae traveling from one 
joint to another, since frequently only one or two joints on a plant 
are found to be infested. Undoubtedly the larvae are cannibalistic in 
habits, and this accounts partly for the fact that these isolated indi- 
viduals are found ; but there is also another factor to be considered. 
The work of the larva? immediately causes a strong reaction on the 
part of the plant. A copious secretion of proliferous tissue is formed 
and larvae have been frequently found completely engulfed in this 
formation. Undoubtedly the pressure frequently results in the 
destruction of the larvae. 

Although this species is an internal feeder, the indications of its 
work are more or less conspicuous. The joint soon takes on a yel- 
lowish appearance and the large swellings on both sides of the joints 
are common sights in the cactus country. The entire interior is 
destroyed and the proliferous growth causes the swellings which 
frequently result in the increase in the thickness of a joint by three 
or four fold. Strangely such swollen joints are sometimes found to 
contain no larvae. The evidence of their work is always present. 
Pressure from the proliferous growth may have caused the death of 
the larvae in such cases. 

The effect upon the plant is generally to cause the death of the 
joint or joints which are infested. The injury is made greater by a 
number of scavengers, principally dipterous. As the larvae fre- 
quently make their way through the stem from one joint to another, 
it is not uncommon for several joints to be killed outright. Of course 
the portion of the plant above the infested joints dies from lack of 
nutrition. After a time the wind causes the diseased branch to fall 
to the ground. In case the larvae are killed by pressure the swelling 
subsides. The sides, however, do' not unite and the joint remains 
deformed. Mr. J. D. Mitchell, who has made many careful observa- 
tions on this species, believes that the partial healing of the injury 
follows when the exit is at the lowest part of the stem, and that the 
joint falls invariably when the exit is near the top and the softened 
excrement and proliferous tissue can not escape. 

Although this insect is not extremely abundant in any locality 
where observations have been made, it is to be found throughout the 
cactus area. In some localities at least one plant in every clump has 



SPECIES ATTACKING JOINTS INTERNALLY. 27 

some portion infested. The total damage done is consequently con- 
siderable. 

DIVERSITY OF HABITS. 

All of the Melitaras reared from cactus during the course of this 
investigation have been identified by Dr. H. G. Dyar as Melitara 
junctolineella Hulst. However, certain peculiarities in habits have 
been observed which lead to the suspicion that more than one form 
may occur. In the region south and east of San Antonio, Tex., the 
only form occurring makes no opening through the surface of the 
joint, but packs its excrement in the cavity made in the process of 
feeding. This form spins a cocoon on the joint or on the ground in 
case the joint has fallen, but this cocoon is not intermixed with sand 
or dirt. In the region from Kerrville, Tex., westward, a form occurs 
which invariably provides an orifice in the joint of the Opuntia 
through which the excrement is dropped to the ground. This gives a 
characteristic appearance of the joint which is easily recognized at 
a considerable distance. This form seems invariably to enter the soil 
for pupation, and a considerable amount of sand is intermixed with 
the cocoon spun for the protection of the pupa. 

DESCRIPTION Or IMMATURE STAGES. 

The Larva. 1 

Early stages whitish ; subsequent stages up to the last deep indigo-blue; 
last stage, 30 to 50 mm. long, conspicuously banded. These bands are dark 
brown and occupy the posterior quarter of each segment. Head 2.5 mm. 
wide, dark brown; clypeus rather deeply emargiuate, with light colored band 
at base. Anal plate almost semicircular in outline, yellow; feet yellow, 
crochets in ellipses; skin plainly wrinkled on dark annulations, less wrinkled on 
lighter portions; spiracles elliptical, one and one-half times as long as broad, 
deep black; thoracic legs light brown; hair very sparse, light yellowish, con- 
fined to head, sides, and underside. 

The Pupa. 

Incased in loose silken cocoon, sometimes intermixed with sand. 25 mm. long 
by 9 mm. wide, uniform mahogany blown, spiracles darker; head and thorax 
transversely rugose; anterior portion of abdominal segments very finely punc- 
tured; posterior portions more sparsely punctured and slightly wrinkled. 

PARASITE. 

A tachinid parasite of this species, Phorocera comstocli "Williston, 
is common. It has been reared from material collected throughout 
the cactus area. 

CONTROL. 

The process of singeing the spines of prickly pear preparatory to 
feeding undoubtedly destroys many of the eggs of this species. In 

l The larva described by Dr. Dyar as probably that of M. junctolineella (Froc. D. S. 
Nat. Mus., vol. 25, p. 396) evidently belongs to some other species. 



28 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



experimental plantings the use of the gasoline torch in the spring 

and the burning of the joints that appear injured will keep the species 

in check. 

Melitara dentata Grote. 

Melitara dentata was described by Grote in 1876 from Colorado. 
In 1892 Prof. V. L. Kellogg published an account 1 of the transforma- 
tions of the species in the leaves of Opuntia missouriensis taken in 
eastern Colorado. All stages were described and illustrated. The 
occurrence of blue and white larvae, which we have observed fre- 
quently in the case of Melitara junctolineella, was noted by Prof. 
Kellogg. 

The same species was collected by Mr. David Griffiths in Trinidad, 

Colo., in June, 1906. 
From this material 
a large number of 
parasites, Chelonus 
laticinctus Cresson 
(fig. 2) , were reared. 

Melitara prodenialis 
Walker. 




Fir:. 2. — Chelonus laticinctus, a parasite of a cactus insect 
Melitara dentata: Adult. Enlarged. (Original.) 



The species Meli- 
tara prodenialis of 
Walker was de- 
scribed in 1863. In 
1877 Miss Mary 
Treat sent cocoons 
from Opuntia poly- 
ant ha collected at 
Green Cove Springs, 
Fla., to the Bureau of Entomology. In 1895 Mr. H. G. Hubbard 
published an interesting account of the oviposition of the species on 
Opuntia vulgaris at Crescent City, Fla., and also included an account 
of the habits of the larva?. Previously Dr. J. B. Smith 2 had de- 
scribed briefly the method of placing the eggs on the plant. These 
few records constitute all that has ever been published concerning 
the species. • i 

The notes on oviposition of this species and the habits of the larvsB, 
made by Mr. H. G. Hubbard, are as follows : 

The eggs are laid at night, and the operation of depositing thorn has not heen 
observed. It must, however, be a wonderfully interesting performance. The 
egg-stick * * * is 80 mm. long. The separate eggs are cylindrical and 



1 Kans. T T niv. Quarterly, vol. 1, pp. 39-41. 

2 Entomological News, vol. 3, p. 208, 1892 



SPECIES ATTACKING JOINTS INTERNALLY. 29 

measure 2 mm. in length by 7 mm. in width. The surface is beautifully 
reticulated with wavy raised lines anastomosing obliquely. The eggs are 
cemented together with a brownish glue which, under the pressure exerted upon 
the mass, is squeezed out at the sutures between each two eggs in the stick 
and hardens there, forming a ring or collar which always adheres to the egg 
beneath when two eggs in the stick are separated. It sometimes has the appear- 
ance of a circle of spinules, owing to the corrugations of the surface upon which 
it is moulded. 

The young larvae of Melitara prodenialis, on hatching from the eggs, feed for 
a time externally upon the bud-like leaves of Opuntia. When they become 
larger and stronger they cut through the silicious skin of the pads. The wounds 
made by them in the plant exude a gummy liquid, and a scab-like crust is 
formed. Under this the larvae live in companies, large or small, according to 
the size of the plant, until they are about one-third grown. After this they 
burrow deeply into the substance of the succulent steins. The larva?, as long 
as they live upon or near the exterior of the plant, are light brown in color, 
but after they burrow into the pulp and approach their full size, they attain a 
most beautiful dark-blue color. In pupating they form a loose cocoon of yellow 
silk, which is concealed somewhere about the Opuntia clump, usually under a 
prostrate pad. 

There appear to be two broods produced during the year, since 
moths were found issuing in Florida in June and again in October. 

Melitara fernaldialis Hulst. 1 

This species, which occurs in Arizona and New Mexico, has not 
been found breeding in Opuntia, but was found by Mr. Hubbard to 
infest the giant cactus, C evens giga.nteus. In all probability it will 
be found to attack Opuntias in the region in which it occurs. In 
fact, in May Mr. F. C. Pratt discovered a larva which may have been 
of this species in Opuntia engelmcmni at Tucson, Ariz. This larva 
discharged its excrement through an opening in the surface of the 
leaves exactly as does the form which occurs in the western portion 
of Texas. Apparently the same form was observed by Mr. Pratt at 
Albuquerque, N. Mex., in June. At Sante Fe, N. Mex., during the 
same month, about 30 per cent of the plants of Opuntia arborescens 
were more or less injured. Unfortunately, it was impossible to rear 
any of these larva 1 . Our supposition that they were of the species 
fernald-ialis is based upon the known range of that form and the 
fact thai they appeared to be different from the Melitara larvae ob- 
served in Texas. 

Gerstseckeria porosa Le Conte. 2 

The presence of the weevil Gersteecheria porosa Le Conte is readily 
shown by the occurrence of flat discolored areas about three-fourths 
inch in diameter on the surface of the joints. In the early stages of 
attack these areas are yellowish, but later become whitish. They 
cover the cavities excavated by the larva?. 

1 Order Lcpidoptera, Family Pyralida\ 

2 Order Coleoptera, Family Curculionidae. 



30 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



This species is distributed throughout the cactus region. It has 
been taken as far north as Denver, Colo., and as far south as San 
Diego, Tex. Its range extends into Arizona. 

The winter is passed in the pupal state within the cells in the 
Opuntia joints. The adults issue from April to June. There ap- 
pears to be only one brood during the season. The species is re- 
sponsible for a large amount of disfiguration of the cactus joints, but 
as the cells are largely superficial the growth of the plant is not 
seriously affected. In fact, in no cases observed have the joints been 
found to be destroyed primarily by the insects. In some cases, how- 
ever, the cells attract scavengers of various species, which increase 
the diseased area and may cause the destruction of the joints. The 
adults appear to feed by scraping the epidermis from the sides of the 

joint. 

Gerstseckeria nobilis Le 
Conte. 

The work of Gers- 
tceckeria nobilis Le 
Conte (fig. 3) is pre- 
cisely like that of the 
preceding species ex- 
cept that the cells con- 
taining the immature 
stages are located on 
the margins of the 
joints. In these locali- 
ties a hard black ex- 
udation frequently forms, and this interferes with the development 
of new growth. For this reason it is more important than the pre- 
ceding species, although it is of less extensive distribution. Our 
records include many localities in Texas from Dallas to Corpus 
Christi. It does not appear, however, to extend far to the west, 
Hondo being the westernmost locality in our records. 

Gerstaeckeria clathrata Le Conte. 

Gerstwckeria clathrata Le Conte works exclusively on Opuntia 
leptocaulis, so far as known, although it may rarely infest allied 
species. Its work in the plants is similar to that of the other species. 
It is partial to the new growth, which is often killed. Although 
thus more destructive than the preceding forms, it is of less economic 
importance on account of the uselessness of its host. It is recorded 
from Colorado to Brownsville, Tex., and westward to Arizona. 

A fourth species, G. hubbardi Le Conte, was reared from Opuntia 
vulgaris in Florida by Mr. H. G. Hubbard. It appeared to follow 
the work of Melitara prodenialis Walker. 




Fig. 



-A cactus weevil, Gerstmckcria nobilis: Adult. 
Enlarged. (Original.) 



SPECIES ATTACKING JOINTS INTERNALLY. 



31 



The four species described are true cactus insects, being dependent 
upon the plant for food and places for breeding. Although only- 
four species have been discovered breeding in cactus, it is likely that 
upon investigation other species of the genus will be found to injure 
it. The genus contains 22 species, of which 11 are found in the 
United States and the remainder in Mexico. 

It is doubtful whether it will ever be necessary to resort to control 
measures in the case of any of the species of Gerstseckeria. If con- 
trol should become necessary, it would be extremely difficult on ac- 
count of the fact that the immature stages are passed beneath the 
surface of the joint. No remedy except the removal of the infested 
joints can be suggested. 

Marmara opuntiella Busck. 1 

The tineid moth. Marmara opuntiella Busck (fig. 4), deposits its 
eggs just beneath the epidermis of the leaves of Opuntia. The first 




m^TrC^^^^m 








Fig. 4. — A cactus insect, Marmara opuntiella: <i. Adult : b, larva; c, eggs and pupal case. 

Enlarged. (Original, i 

indication of injury is a slight elevation of the epidermis above the 
gallery which the larvae have begun to excavate. The first attack 
(PI. VI) is generally near the base of the joint. Later the epidermis 
above the galleries becomes white and the galleries may cover the 
entire surface of the joint. This is certain to be the case where sev- 
eral eggs are deposited in one joint. A gummy exudation appears 
and the whole surface of the joint becomes covered with a yellownsh 
secretion that conceals the mines. The larva? work immediately 
beneath the epidermis and never penetrate the interior of the joint. 
On this account they have little effeci upon the growth of the plant. 
Only on rare occasions when the attack has been directed against the 
new growth does the joint fall to the ground. The species is widely 
distributed in Texas, having been taken from New Braunfels south- 
ward to Brownsville. 



1 Order Lepidoptera, Family Tineidae. 



32 PKINCIPAL CACTUS INSECTS OF UNITED STATES. 

The only cases in which it will be necessary to combat this insect 
will be those in which the new growth of the plants is affected. The 
only course to follow is to remove these joints and burn them. 

SPECIES INJURING THE BLOOMS. 

In the category of species injuring the blooms there is only one 
that is of importance. This is Trichochroiis (Pristoscelis) texanus 
Le Conte. It is a slender beetle, 3 mm. in length, uniformly oliva- 
ceous above, highly polished, with reddish legs, the upper surface of 
the body covered with rather dense growth of short whitish hairs. 
It has been collected at southwestern Texas and in New Mexico. At 
Albuquerque, in the latter State, on June 16, Mr. F. C. Pratt found 
it in such abundance that no blooms without indications of injury 
were noticed. The great majority of the plants had been fed upon 
to such an extent that fruiting had ceased. As many as 153 beetles 
were found in a single bloom. No larvae could be found in the 
vicinity. It is possible that this species is not at all peculiar to 
cactus, but is to be found in blooms of various kinds. There was a 
remarkable absence of flowers on all plants except the Opuntias 
growing at Albuquerque at the time to which reference has been 
made. This may account for the concentration of the insects in the 
blooms of the Opuntias and for the damage accomplished. No simi- 
lar cases had been observed, in the numerous observations that had 
been made in Texas. 

Euphoria kernii Haldeman 1 is a very common beetle in cactus 
blooms in Texas. It is a robust species of very variable color. Some 
specimens are pure black and all gradations between this form and in- 
dividuals in which the ground color is yellow, but covered with nar- 
row black stripes, are to be found. The species seems to feed upon 
the columns and anthers more than upon the petals. Even where it 
is so abundant that several individuals are to be found in every 
bloom no special injury to the plants has been detected. On this 
account the species is included in the list at the end of this bulletin 
as one which has no other association with the cactus plant than that 
it frequents the bloom. 

SPECIES INJURING THE FRUIT. 

Narnia pallidicornis Stal. 

Of the species that injure the fruit, by far the most important are 
the bugs of the genus Narnia, the most common being N. pallidicornis 
Stal. 2 The species can be recognized readily. (PI. VII, fig. 4.) It 
is of a brownish-yellow color, about 15 mm. in length. The posterior 
femora^ are lengthened, very robust, and covered with heavy black 

1 Order Coleoptera, Family Scarabseidae. 2 Order Hemiptera, Family Coreidae. 



Bui. 1 1 3, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VI. 




Joint of Prickly Pear, Showing Work of Marmara opuntiella. (Original.) 



Bui. 1 13, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VII. 




Studies of Cactus Insects. 



Fig. 1.— Eggs of Melitara mnctolineella on spines of Opuntia. Fig. 2.— Eggs of Chelinidea vittigera 
onspine ot Opuntia. Fig. ;;.— Eggs of Copestylum marginatum on Opuntia spines. Fig. ■!.— 
Narma pallidicornis. (Original.) 



SPECIES INJURING THE FEUIT. 33 

spines. The posterior tibia- are expanded just beyond the middle 
into fanlike dilations. 

This insect is essentially an enemy of the fruit of the Opuntias. 
Although it has been observed very commonly in Texas, it has never 
been found to injure the joints. Like the bugs of the genus Che- 
linidea, it and its immediate relatives are gregarious in their habits. 
The range extends from Mineral Wells, Tex., southward to Browns- 
ville and westward to El Paso. 

DESCRIPTIVE. 

The Egg. 

Egg. — Length, 1.5 mm.; width. 1 mm. Dark brown in color, cylindrical, 
sharply truncate at both ends, surface very finely roughened. Toward the 
upper end the lid appears as a raised spot with a light ring. Placed with ends 
contiguous on cactus spines, from 12 to 25 on a spine, sometimes several strings 
alongside of each other on (he same spine. Length of egg stage, about 27 days. 

The Nymphai. Stages. 

First instar. — When first hatched, the bugs are slightly less than 4 mm. in 
length, orange iu color, but soon change to a reddish hue. Antennae brown, 
4-.iointed, club and first joint equal, second joint slightly louger, basal joint 
barely one-half the length of the others; all joints covered with hairs, those on 
the club shorter. Legs reddish, hairy; tarsi dark brown, having shorter hairs. 
Head reddish; eyes brown; pronotum reddish and armed with a pair of erect 
spines; abdomen reddish, with four pairs of red spines located on the first, 
second, fourth, aud fifth segments. Margins of abdomen with a row of six 
erect spines, those at base being longest. Each spine terminates in a short, 
black, motile bristle. The third and fourth pairs of spines are located on a 
raised callosity. Length of this stage. 7 days. 

Second instar. — Length. 5 mm. Antenna? lighter in color than in previous 
stage, except club, which is dark brown; front and middle pairs of legs yellow, 
posterior pair darker, dilations on tibiae now appearing: terminal tarsal joints 
bearing claw, which is dark brown: head, thorax, and pronotum dark brown: 
front of head yellow, abdomen reddish. Spines as in first stage, the pronotal 
spine -being twice the length of the others. Length of this stage, 7 days. 

Third instar. — Length. 6 mm. General color of body brown: antenna?, except 
club, and front and middle pairs of legs yellow; club of antenna? and posterior 
legs brown, except joints and tarsi, which are yellow ; callosities on pronotum 
and margins of abdomen whitish, those on abdomen black. An additional pair 
of spines appears on thorax. Length of this stage. 13 days. 

Fourth instar. — Length, !> mm. Antenna- as in third stage. General color 
dull velvety black and speckled as if dusted with white powder; sparsely 
covered with shiny, white hairs, those on posterior legs longer and more dense; 
abdomen reddish heneath. Leugth of this stage, five days. 

Fifth mstar. — Length. 15 mm. Same coloration as preceding stage, hairs 
apparently more dense, pronotal spines yellow at base. Thorax well defined. 
Wing-pads have now appeared, extending over pronotum, yellow. Abdomen 
yellow, beneath black. Length of this stage, 7 days. 

50975°— Bull. 113—12 3 



34 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



As has been stated, this is an important enemy of the Opuntia 
plant where the fruits are desired for food. In cactus plantations, 
however, where the plants are reproduced by cuttings, it is of com- 
paratively little importance. On account of its gregarious habits 
and its location on the parts of the plant easily reached by a gasoline 
torch, its control is not a difficult matter. 

There are three other species of Narnia which feed upon the fruit 
of Opuntia and related plants. After pattidicomig, the most com- 
mon species is fem-orata, which is as widely distributed in Texas as 
that species and extends its range as far westward as Los Angeles, 
Cal. It has also been taken in Mexico at Aguascalientes, Victoria, 

and Durango. In general appear- 
ance it resembles pallidicomis very 
closely, but is somewhat larger. N. 
pallidicomis has the dilation of 
the hind tibia narrower, lanceolate 
shaped, and the inner part of the 
dilation broadest behind the middle. 
The remaining species of the 
genus which we have observed on 
cactus are inornata and snowi. The 
former has been taken in California 
and Mexico only, while we have only 
a single record of the latter species, 
at Albuquerque, X. Mex., in April. 

Asphondylia opuntise Felt. 1 

Asphondylia opuntuc Felt ranks 
next in importance to the Xarnia 
bugs so far as injury to the fruits 
of Opuntia is concerned. It is not 
restricted, however, to the fruits, 
but sometimes infests the margins 
of the joints. Its presence is first detected by a yellowish coloration 
of the fruit or joint and later by the protruding puparia in close 
groups of sometimes as many as 10 individuals (fig. 5). 

This species has a wide range. Specimens have been taken at many 
points in Texas and southward to San Luis Potosi, Mex., and west- 
ward to Los Angeles, Cal. There are evidently several generations 
in the season, the first adults appearing in southern Texas in March. 
Especially in California this species is extremely abundant. On 
this account it is fortunate that its injury primarily affects the fruit 
and does not interfere seriously with the growth of the plant. Tt 




Fig. 5. — Opuntia fruit with puparia of 
Asphondylia opuntia. Enlarged. 
(Original.) 



Order Diptera, Family Cecidomyiidce. 



SPECIES INJUKING THE FRUIT. 35 

can not interfere seriously with the production of forage. It is of 
greatest importance in Mexico, where the fruit of the Opuntia plant 
is a very common article of diet for the natives. 

Instances of curious deformations of the plant result from the 
work of this fly. The infested fruit, instead of developing as such, 
is transformed into a very short joint, which gives rise to a larger 
or nearly normal joint. The remarkable change in the appearance 
of the plant caused in this way is sometimes very conspicuous. The 
result of the work of the same or a similar species was described as 
an abnormal fruit of Opuntia ficus-indica from Caracas by A. Ernst. 1 

Three additional species of Cecidomyiida3 have been reared from 
Opuntia. They are included in the list at the end of this bulletin, 
but need not be considered in this connection on account of their 
very rare appearance. 

Cornifrons elautalis Grote. 2 

C omifrons elautalis Grote is a small grayish moth infesting the 
green fruits of Opuntia. It was first collected by Mr. J. D. Mitchell 
in Majr, 1908, at Hondo, Tex. Later it was taken at Tucson, Ariz., 
but on the whole seems to be of rare occurrence. The larvae bore into 
the fruit to a depth of 1 inch and eject a reddish-colored excrement 
on the crown of the fruit, causing its death. At Tucson, Ariz., in 
May, Mr. F. C. Pratt noticed that many fruits were injured by these 
larva?. On some plants practically all of the fruits were injured, and 
it was found that the larva? traveled from one fruit to another. In 
that vicinity fully 10 per cent of the fruits were injured. 

The larva? are generally to be found just beneath the corolla, which 
remains on the crown longer than when the fruit is uninjured. 
When the corolla falls the larva? web over the orifice made in the 
fruit, and the protection is augmented by the addition of the reddish 
excrement. They also occur in the blooms, but leave them as soon 
as the flower parts become dry. 

It is evident that eggs are generally deposited in the blooms, 
although this is not by any means invariable. Many fruits were 
observed in which entry had been gained from the side. 

The larva? are blackish, with a shining black head and narrow, 
lateral crimson bands. 

Allorhlna mutabilis Gory. 3 

Mr. E. A. Schwa rz informs us that AllorMna mutahilh (lory is a 
common enemy of the fruit of Cereus in Arizona. It i< well known 
for its damage to fruits of various kinds. 

1 Nature. November S-\. 1882, p. 77. 
- Order Lepidoptera, Family Pyralidse. 

3 Order Coleoptera, Family Scaralneida?. 



36 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Sixeonotus luteiceps Reuter. 1 

The adults of Sixeonotus luteiceps Reuter are 3 mm. long, with 
dark steel-blue wing covers and red head and thorax. The nymphs 
are bright scarlet. The range of the species is in southwestern Texas. 
It is not a true cactus insect, although frequently found upon the 
plant. It seems to prefer yuccas. On these plants it has frequently 
been observed in great numbers, while Opuntia growing in the 
immediate vicinity remained uninjured. When cactus plants are 
attacked the preference seems to be for the ornamental forms of the 
" pitallo " group. When in large numbers it disfigures these plants 
considerably, and sometimes causes their death. The iirst indication 
of injury is a yellowish discoloration, while the surface is covered by 
numerous black specks of excrement. 

Polistes spp. 2 

Two species of wasps of the genius Polistes, namely, rubiginosus 
and texanus, have been taken commonly in Texas, and one, flan/s, 
was taken on Cereus in Arizona by Mr. H. G. Hubbard. The adults 
of these species are found everywhere on the fruit of Opuntia and 
other cacti. They cut open the partially ripened fruit with their 
mandibles and feed upon the juices that exude. They are of very 
little importance from the standpoint of the cultivation of the plant. 

Liotropis contaminatus Uhler. 3 . 

The species Liotropis contaminatus Uhler, recorded by Prof. H. 
Osborn 4 on fruit of Opuntia fulgida near Tucson, Ariz., occurs also 
at El Paso, Tex., and in the Inyo Mountains, Cal., at the latter 
locality at an elevation of 7,000 to 9,000 feet. 

Dytopasta yumaella Kearfott. 

Reared from Opuntia fruit collected at Hondo, Tex., by Mr. J. D. 
Mitchell in June. Also taken in Arizona. 

Ozamia lucidalis Walker. 

Observed at Victoria, Austin, San Antonio, and Hondo, Tex. 
Larva moves from fruit to fruit, thus destroying sometimes as many 
as five. Cocoon whitish, silky, unmixed with foreign matter, placed 
on side of fruit. Evidently Avidespread, but never abundant. 

Platynota rostrana Walker. 

Reared from Opuntia fruit collected at Brownsville, Tex., in May 
by Mr. J. D. Mitchell. This is the only record we have obtained. 

1 Order Hemiptera, Family Capsidse. 3 Order Hemiprora, Family Pentatomidse. 

- Order Hymenoptera, Family Vespidse. 4 Ent. News, vol. ^0, p. 177, 1906. 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



37 



SCAVENGERS. 

In the list of insects found associated with the cactus plant at the 
end of this bulletin we have included 73 species in the category of 
scavengers. Many of these "species feed only upon the joints when 
these have been killed by other insects or when they are blown to the 
ground. A considerable number of the scavengers, however, breed 
in the living joints, obtaining entrance through the mines of Moneil- 
ema, Melitara, and other forms. The diseased condition caused 
primarily by the original inhabitant of the joint is increased by the 
work of such scavengers. They are therefore incidentally injurers of 
the plant. The cavities they inhabit become infested by various 
fungi and bacteria and the diseased area increases in size when, with- 
out the intervention of these scavengers, the plant would be able to 
heal the wound. 

Copestylum marginatum Say. 1 

The most common of the 
scavengers which increase the 
effects of the attack of other 
insects is Copestylum margin- 
atum Say (fig. 6). The adults 
of this fly are to be found about 
the cactus plant from March to 
October. They are also taken 
commonly in the blooms of a 
long list of plants found in the 
cactus region. Undoubtedly 
they breed in decaying vegetation of all kinds, but one of the most 
important breeding places is the joints of cactus that have been 
injured by Melitara, Moneilema, Gerstseckeria, and other forms. 
Very soon the interior of the joint becomes filled with a dark, mal- 
odorous liquid, which undoubtedly causes the rapid decay of the 
plant tissues. 

The adult fly deposits its eggs on the spines in large masses. (PI. 
VII. fig. 3.) 

The larva of this species measures 20 mm. by 4 mm.; the tail is 
1 mm. in length. It is shining, its skin wrinkled. In color it is white, 
the tail dark brown. Each ventral segment has two almost contiguous 
oval areas of very short, stout, brownish spines, and there are similar 
spines on the head segment. The puparium is 10 mm. by 4 mm., 
calcareous, its surface dirty whitish, covered with particles of sand. 
There are many annulations of spinose areas, more distinct beneath. 




Pig. 6. — A cactus insect. Copestylum margin- 
atum: Adult. Enlarged. (Original.) 



1 Order Diptera, Family Syrpbidse. 



38 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



In the same category as the preceding species are four species of the 
closely allied genus Volueella, namely, esuriens, avida, pmilla, and 
faseiata. They have been found numerously in practically all locali- 
ties where cactus insects have been collected, occurring frequently 
with Gopestylum marginatum Say and other species. 

Hermetia spp. 1 

Almost equally important are two species of Hermetia, namely, 
chrysopila (fig. 7) and hunteri. The former is much more abundant 
and occurs from Dallas, Tex., southward to San Antonio and west- 
ward as far as Los Angeles, Cal. 

The larva? of Heimietia chrysopila Loew measure 35 mm. by 10 mm., 
the tail 2 mm. The integument is very tough and leathery, dark 
brown, its surface densely and evenly punctured, with indistinct 

transverse rows of callosi- 
ties near the posterior 
third. The head is deeply, 
longitudinally impressed 
below, with two longitudi- 
nal ridges above. 

This species has been 
collected from April until 
September and has been 
observed depositing eggs 
in the empty cells of Ger- 
sta>ckeria as well as in the 
openings made by Melitara 
and other species. It is 
not at all restricted to 
cactus, but undoubtedly 
breeds in decaying vegetable matter of any description. The adults 
are found in flowers of many species as well as in those of Opuntia. 
The most remarkable observation made on this species relates to 
the longevity of the larva. In May, 1909, a number of specimens 
which appeared to be nearly full grown were taken at Hondo, Tex., 
by Mr. J. D. Mitchell. They were placed in breeding cages, from 
which adults appeared irregularly between July 17 and August 19. 
Some of the larvae, however, did not yield adults. They remained 
motionless in the bottom of the cages. Whenever a new supply of 
food in the form of decaying cactus was introduced they began feed- 
ing, but as soon as the food dried they became quiescent. After it 
was observed that they were of rather remarkable longevity no food 
was introduced for over a year. The larvae lived for more than 15 
months without food and developed readily later when food was sup- 




PlG. 



-A cactus insect, Hermetia chrysopila: Adult. 
Enlarged. (Original.) 



'Order I)ipti'ra. family Stratiomyiidffi. 



LIST OF PRINCIPAL CACTUS INSECTS. 



39 



plied. The very leathery integument seems to protect the insect 
against desiccation, and in other ways the larva has evidently adapted 
itself to long periods of waiting for favorable food, which, in the arid 
regions, depends upon the infrequent rains. 

Stictomyia longicornis Bigot. 1 

The Stictomyia longicorrds of Bigot is an exceedingly common 
insect throughout the cactus area. The adults are small flies with 
spotted wings. The wings are bent downward at about the middle. 
so that the name of " droop-winged fly " seems appropriate. (See 
fig. 8.) The larvae occur along with Copestylum, Volucella, and 
Hermetia in o.ny part of the cactus plant that may be injured. They 
also infest wounds made by knives when cuttings are removed for 
planting. 

The remaining insects 
lifted as scavengers are of 
less general occurrence than 
the species mentioned in 
the preceding pages and 
no special notes have been 
made upon them. 

LIST OF THE PRINCIPAL 
CACTUS INSECTS OF THE 
UNITED STATES. 




Fig. 8. — A cactus insect, Stictomyia longicornis: a 
Adult in profile ; &., head ; c, wing. Enlarged. 
(Original. > 



The following list deals 
primarily with the species 
attacking or associated 
with the genus Opuntia and includes all published records of 
previous investigators. Many forms not restricted to Opuntia are 
included because, as Mr. Schwarz has pointed out, the insects of that 
plant are interchangeable with those of other plants of the family 
Cactacea\ For this reason we have included all of the records of 
species taken on Cereus giganteus in Arizona by Mr. H. G. Hubbard. 2 
The names of such species are preceded b}^ an asterisk. We have also 
included references to some exotic species, principally from Mexico. 

The published records of cactus insects, including those of Mr. 
Hubbard, deal with 105 species. The present list includes 324 spe- 
cies. These are divided, for convenience, into the following groups: 
Injurious 92, parasitic or predaceous 28, scavengers 73, visitors of 
flowers 40. incidental 91. 



1 Order Diptera, Family Ortalidae. 

2 Except Platydemu inquUinum Linell. which was taken in a rat's nest. 



40 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

The determinations in all cases have been made by the recognized 
authorities in the different groups. We are indebted to the following 
entomologists for assistance in this connection: E. A. Schwa rz, 
H. G. Dyar, W. M. Wheeler. Otto Heidemann, W. D. Pierce, J. C. 
Crawford, and S. A. Rohwer. Mr. Schwarz also rendered most 
valuable aid in making suggestions throughout the course of the 
work and in reading the manuscript and proofs. 

AVe are especially indebted to Prof. T. D. A. Cockerell for furnish- 
ing complete lists of Opuntia bees and for making many suggestions 
about the portion of the list dealing with the Coccida?. 

SPECIES WHICH INJURE THE PLANT. 

ARACHNIDA. 

Tetrangchns opuntice Banks. Reported by Mr. David Griffiths as injurious, but 
not taken in present investigations. 

ISOPTERA. 

Termes flavipes Kollar. Sabinal, Tex., September (F. C. Pratt) ; Falfurrias 
and Hondo, Tex. (J. D. Mitchell). 

Attacks young Opuntia plants, also Cei - eus; frequently nests in decaying 
Opuntia and constructs covered galleries on joints. 

HEMIPTERA. 

Liotropis contaminatus Uhler. Tucson, Ariz.; El Paso, Tex. (H. F. Osborn). 

Feeding on fruit of Opuntia fulgida. 
Chelinidea tabulata Burmeister. Durango, Aguascalientes, and Victoria, Mex. ; 
Tucson, Ariz. ; Brewster County, Devils River, Oakville, Victoria, Austin, 
Hondo, and San Antonio, Tex. Throughout the season. 
Feeds on joints. 
Chelinidea vittigera Filler. Colorado, Abilene, San Antonio, Knickerbocker, 
Trinity, Cotulla, Tivoli, Boerne, Encinal, Victoria, San Diego, Kerrville, 
Dallas. Oakville, Chisos Mountains, Mineral Wells, Hallettsville. Sabinal, 
Hondo, Falfurrias. Laredo, Fredericksburg, El Paso, and Austin, Tex. 
Throughout the season. 
Feeds on joints. 
Chelinidea sp. Tucson, Ariz., May (F. C. Pratt). 

Feeding on joints of Opuntia fulgida. 
Largus succinctus Linnaeus. San Antonio, Tex., July (F. C. Pratt). 

Feeding on joints of Opuntia arborescens. 
Lopidea cuneata Van Duzee. Los Angeles, Cal., June (F. C. Pratt). 

Feeds on joints of Opuntia. 
Oncerometopu8 nigriclavus Router. Kerrville, Tex.. August (F. C. Pratt); 
D'Hanis, Tex.. April (.7. D. Mitchell). 
Feeding on joints of Opuntia. 
Hadroncniti robuata Uhler. San Antonio, Tex., June (J. C. Crawford). 
Feeding on joints of Opuntia. 



SPECIES WHICH INJURE THE PLANT. 41 

Stylopiden picta Filler MS. Victoria and D'Hanis. Tex., April (J. D. Mitchell) : 
San Antonio, Tex., April (J. C. Crawford) ; Hondo, Austin, and Corpus 
Christi, Tex., May (F. C. Pratt) ; Brownsville. Tex., February (C. R. Jones 
and F. C. Pratt) : Beeville, Tex. (E. A. Schwarz). 
Feeds on joints. 
Sixeonotus luteiceps Reuter. Hondo, Tex., May (J. D. Mitchell) ; Brownsville, 
Tex., March (C. R. Jones and F. C. Pratt). 

Feeds on joints; esj>ecially partial to Echinocereus spp. ; also taken on 
yucca and other plants. 
MacrotylUH verticali8 Uhler (?). Los Angeles, Oal., June (F. C. Pratt). 

Feeds on joints of Opuntia. 
Gorytliuca decern Still. Aguascalientes, Mex., December (F. C- Pratt). 
On Opuntia. 
Tucson, Ariz., June (J. W. Tourney). 
Feeding on Opuntia joints. 
Proarno valvata Filler. Albuquerque. N. Mex., May (F. C. Pratt). 

Apparently feeding on Opuntia joints. 
Namia femorata Stftl. Taken at the following localities in Texas throughout 
the season: Mineral Wells (C. R. Jones) ; D'Hanis, Cotulla, Corpus Christi, 
Victoria, and llehbronville (J. D. Mitchell) ; Hondo, Zavalla County, Sabi- 
nal, San Antonio, Kerrville, El Paso, and Llano (F. C. Pratt) ; also taken 
at Los Angeles, Cal., and Tucson, Ariz. (F. C. Pratt), and at Aguascalientes, 
Victoria, and Durango, Mex. (F. C. Bishopp). 
Feeds on fruit of Opuntia and on Cereus; very destructive. 
* Dendrocoris contaminatus Uhler. Tucson, Ariz. 

Xnntia pallidicomis Stal. Taken in Texas at localities below: Cotulla, Kerr- 
ville. El Paso, Sabinal, Austin (F. C. Pratt) ; Alice, Hondo, San Antonio, 
D'Hanis, Hebbronville. San Diego, Victoria, Encinal, and Oakyille (J. D. 
Mitchell) : Mineral Wells (C. R. Jones). 

Occurs throughout the season ; very destructive to fruits. 
Narnia inomata Distant. Los Angeles, Cal., May (F. C. Pratt); Durango, 
Mex., November (F. C. Bishopp). 
Feeds on joints. 
Namia snovn Van Duzee. Albuquerque, N. Mex., April (F. C. Pratt). 

Feeds on joints. 
Platypedia putnami Chler, Albuquerque, X. Mex., June (F. C. Pratt). 

Feeds on Opuntia joints. 
Platymetopius fuseifrons Van Duzee. D'Hanis, Tex.. April (J. D. Mitchell). 

Feeds on joints. 
Dictyobia permit fata Uhler. Corpus Christi. Tex. (F. C. Pratt and A. C. 
Morgan ) . 

Feeds on joints. 
Aphis medico g>» is Koch (det. C. E. Sanborn). Tucson, Ariz., May (F. C. 
Pratt) : Hackberry, Ariz. |D. Griffiths) ; Dallas, Tex. (F. C. Pratt). 
On Opuntia. Mr. Sanborn informs us that in Texas the species prob- 
ably passes the winter on Opuntia. 
Margarodcft sp. (?). Montserrat. W. I. (C. V. Riley). According to Prof. 
Cockerel! (in litt.) the species is undoubtedly M. formicarum (Guild.). 
On Cereus roots. 
Eriococcus con-incus Cockerell San Bernardino, Cal.. September; also from 
greenhouse in Nebraska. 
On joints. 



42 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Dactylopius confusus Cockerell. (Cottony cochineal insect.) Throughout the 
cactus region from Graham County, Ariz., southward, Texas, Florida, and 
California. 

Feeds on joints of all species of Opuntia. 
Also present in hothouses throughout the country. 
Dactylopius (Coccus) near confusus. Barbados, W. I., May (D. D. Morris). 
Dactylopius coccus Costa. (Cochineal insect.) Recorded from California and 
Florida, but probably introduced. Introduced in West Indies, Canaries, 
India, Peru, Spain, and other Mediterranean countries. 
Dactylopius foment osus Lamarck. Guanajuato, Mex., July (T. D. A. Cockerell ) ; 
New Mexico; Arizona. 
On Opuntia fulgida joints. 
Dactylopius (Coccus) sp. Cape Town, South Africa (A. M. Cooper). 

On Opuntia polyantha. 
Dactylopius (Coccus) sp. Colorado Desert, Cal., January (D. W. Coquillett). 

San Bernardino, Cal. 
Pseudococcus virgatus Cockerell. Brownsville, Tex. 

On "Jacobo" cactus. (See also Cockerell, Can. Ent, 1S95, p. 259.) 
Pseudococcus obscurus Essig. California. 

On roots of Opuntia. 
Pseudococcus longispinus Targioni-Tozzetti (Syn. : Dactylopius longifilis Corn- 
stock ) . 

(See Lintner, 2d N. Y. Report, p. HO.) 
On prickly pear at Waterbury, Conn. 
Pseudococcus sp. Mesilla Park, N. Mex., April (D. Griffiths). 

On joints of Opuntia cycloides. 
Ripersia sp. 

On roots of cactus. 
Diaspis cacti Comstock. Arizona and New Mexico. 

On Opuntia fulgida, O. arborescens, and O. cngelmanni. 
Diaspis cacti opunticola Newstead. Demarara. 

Diaspis ccliinocacti Bouche. According to Mrs. Fernald, Europe, India, Algeria, 
Porto Rico, Mexico, New Mexico, New York. 

On Opuntia ficus-indica, Echinocactus ottonis, and E. tcnuispinus, etc. 
Diaspis ccliinocacti cacti Comstock. Laredo, Tex., March, on Opuntia leptO- 
caulis and 0. lindhcimcri (F. C Pratt) ; San Antonio. Tex. (J. D. Mitch- 
ell) ; Arizona and New Mexico, on O. fulgida, 0. arborescens, and 0. engel- 
manni (T. D. A. Cockei-ell). According to Mrs. Fernald, Massachusetts 
and New York (greenhouses), Iowa, Arizona, New Mexico, Brazil, India, 
Mauritius, on Cactus, Cereus giganteus, C. macrogonus, Echinocactus sp. 
Diaspis eehinoeacti opuntice Cockerell. Kingston, Jamaica (T. D. A. Cock- 
erell) ; Sierra Blanca, Tex., on Opuntia arborescens (C. H. T. Townsend) ; 
Demarara. Texas, Mexico, on O. arborescens and O. elongata. 
Pseudoparlatoria parlatorioides Comstock. Frontera, Mex. (C. H. T. Town- 
send ) . 
Lepidosaphes (Opuntiaspis) philocoecus Cockerel). On Opuntia in Mexico, ac- 
cording to T. D. A. Cockerell in litt. 

COLEOPTERA. 

Trichochrous (PristosceUs) texanus Le Conte. Albuquerque, N. Mex., June, 
Zavalla County, Tex. (F. C. Pratt) ; D'Hanis and Brownsville. Tex. (J. D. 
Mitchell). 

Occurs in great numbers in blooms, which are sometimes considerably 
injured. 



SPECIES WHICH INJURE THE PLANT. 43 

Allorhina mutabilis Gory. According to Mr. E. A. Schwarz feeds on fruit of 
Cereus. 

Moneilema ulkei Horn. Cotulla. Falfurrias, and Brownsville, Tex. (J. D. 
Mitchell) ; Sabinal, Tex. (F. C. Pratt) ; Oakville, Tex. (F. C. Bishopp). 
Larvae in roots ; adults feed on joints. 

Moneilema variolate Thomson. Mexico (Duges). 
Breeds in " Cactus Opuntia." 

Moneilema armulatum Say. 

On Opuntia in Kansas (Popenoe.) 

Moneilema semipunctatum Le Conte. 

On Opuntia in Kansas (Popenoe.) 

Moneilema crassum Le Conte. Cotulla and Maverick counties, Tex., May 
(J. D. Mitchell) ; Encinal, EI Paso, and Sabinal, Tex.. April to September 
(F. C. Pratt). 
Larva? in roots; adults feed on joints. 

Moneiiema spoliatum Horn. Encinal. Tex., May (D. Griffiths). 
Larva; in roots; adults feed on joints. 

Moneilema Iwvithoraw White. Mex. 

* Moneilema gigas Le Conte. 

Moneilema armatum Le Conte. 

Moneilema sp. Falfurrias, Tex., April (J. D. Mitchell). 

Coenopceus palmeri Le Conte. Bred from stems of Opuntia bcrnardina. South- 
ern California. 

Disonyeha varicornis Horn. Devils River. Tex., May (E. A. Schwarz and F. C. 
Pratt) ; San Antonio and Austin, Tex., April, August, and June (F. C. 
Pratt). Confined to Opuntia leptocaulis and similar species. 

Gcrstackeria hubbardi Le Conte. Breeds in the joints of Opuntia vulgaris fol- 
lowing injury by MeUtara sp. ; taken at Crescent City and Lake Worth, 
Fla., and Selma. Ala. (H. G. Hubbard and E. A. Schwarz). 

Gersta;ckeria bifasciata Gerstaecker. Reared November 1, 1910, by F. L. Lew- 
ton from Echinocactus setispinus collected in June at San Antonio, Tex. 

Gcrstackeria nobilis Le Conte. Breeds in the margins of the joints of Opuntia 
engelmanni and causes great masses of black excrement and gum to form 
on the outside of the joint. It has been taken at Dallas, Tex. (J. Boll) ; 
San Antonio, Tex., November (H. Soltau) ; San Diego, Tex., April, May, , 
September (E. A. Schwarz) ; Beeville, Tex., April, eating fruit of Opuntia 
(C. L. Marlatt) ; Cotulla, Tex., April (F. C. Pratt) ; Live Oak County, Tex., 
June (J. D. Mitchell) ; Floresville, Tex., October (F. C. Pratt) ; Corpus 
Christi, Tex., May (A. C. Morgan), March (W. E. Hinds); Hondo, Tex.. 
April (J. D. Mitchell) ; College Station, Tex., March (W. D. Pierce) ; 
Encinal, Tex., April (J. D. Mitchell) ; Victoria, Tex., April (J. D. Mitchell). 

Gerstackeria porosa Le Conte. Denver, Colorado Springs, Colo. (Wickham 
and Soltau) ; Sedalia, Colo. (II. Soltau) ; Albuquerque, N. Mex. (H. Soltau) ; 
Mesilla Park, N. Mex. (C. N. Ainslie) ; Kansas (Snow) ; Fort Grant, Ariz. 
(H. G. Hubbard and E. A. Schwarz) ; San Diego, Tex. (H. G. Hubbard and 
E. A. Schwarz) ; Floresville, Tex. (F. C. Pratt) ; Live Oak County, Tex. 
(J. D. Mitchell); DTlanis, Tex. (J. D. Mitchell); Hondo, Tex. (F. C. 
Pratt). 
The species breeds in flat cells in the discs of the joints of Opuntia. 

Gersta-rkeria basalis Le Conte. Denver. Colo (H. Soltau); Greeley and Canon 
City. Colo. (H. Soltau) ; Sioux County, Nebr. (R. H. Wolcott). 



44 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Gerstceckeria claihrata Le Conte. - San Diego, Tex., April and May, Laredo, 

Tex. May (H. G. Hubbard and E. A. Schwarz) ; Hidalgo, Tex. (G. Beyer) ; 

Uvalde, Tex., June (H. F. Wickham) ; Brownsville, Tex., June (C. H. T. 

Townsend) ; Santa Rita Mountains, Ariz., May (H. G. Hubbard and E. A. 

Schwa rz ) . 
Breeds in Opuntia leptocaulis. 
Gerstceckeria turbida Le Conte. Catalina Springs, Ariz., April (H. G. Hubbard 

and E. A. Schwarz) ; Tucson, Ariz.. January (H. G. Hubbard and E. A. 

Schwarz) ; Fort Grant, Ariz., July (II. G. Hubbard and E. A. Schwarz). 
Gerstceckeria opuniice Pierce. Encinal. Tex., April (J. D. Mitchell). 
Gerstceckeria cactophaga Pierce. Port Isabel, Tex., May (H. S. Barber) ; 

Brownsville, Tex. (C. H. T. Townsend). 
Onychobaris mystica Casey. Southern Texas, Arizona, and New Mexico, on 

Opuntia leptocaulis (E. A. Schwarz) ; Tucson, Ariz., in O. fulgida. 
*Cactophag'us spinolce Gyllenhal (Syn.: validus Le Conte). (See Champion, 

Biol. Centr.-Amer. ) California, Arizona, Mexico, many localities. Larva 

and pupa figured by Duges (La Naturaleza, vol. 5, 121). 
According to Duges breeds in " Cactus opuntia." 
Caclophagns striatoforatus Gyllenhal. Attacks Cereus in Costa Rica and Co- 
lombia. (Sec Champion. Biol. Centr.-Amer.. Coleoptera, vol. 4, 7, p. 84. 
* Cactopinus hubbardi Schwarz. Forms mines in Cereus. 

LEPIDOPTEKA. 

Apantcsis urge Drury. 

Feeding on cactus. (See Forbes, 23d Rept. Ins. 111., p. 777, 100.".) 

Chorisagrotis soror Smith. San Antonio, Tex., February (D. Griffiths). 

Larvae had formed canals through underground portions of plants. A serious 
enemy of young plantings. According to Dr. Dyar, it is probably a general 
feeder and not confined to cactus. 

Mimorista flavidissimalis Grote. Widespread in Texas, south of San Antonio 
and west of Victoria. Brownsville, Victoria, and Beeville (J. D. Mitchell), 
San Antonio and Sabinal ( F. O. Pratt); May to September. A very 
destructive insect, attacking joints of Opuntia. 

Cornifrons elautalis Grote. Hondo, Tex. (J. D. Mitchell) ; Tucson, Ariz. 
Destructive to fruit. 

Dicymolomia opuntialis Dyar. San' Diego and Riverside, Cal., May (D. Grif- 
fiths). Apparently forms mines in joints, but doubtfully included in this 
lisl Sec following species. 

Dicymolomia julianalis Walker. Brownsville and Kerrville, Tex., June. Ap- 
parently forms mines in joints, but it is very doubtful whether it should 
be considered a cactus insect. Gahan (Proc. Ent. Soc. Wash., vol. 11, 
p. 66) records it as a predator on the eggs of Thyridopteryx ephemerce- 
formis Haworth. 

Ozamia lucidalis Walker. Victoria, San Antonio, and Hondo, Tex., May (J. D. 
.Mitchell i. Infesting fruit. 

Melitara junctolineella Ilulst. Kerrville, Tex. (H. Lacy) ; Corpus Christi, Vic- 
toria, Beeville, Hondo, Laredo. Tex. (J. D. Mitchell) ; El Paso, Kerrville, 
San Antonio, Tex. (F. C Pratt). This and the other species of the genus 
live within the joints of Opuntia. causing large swellings. The two dif- 
ferenl kinds of cocoons seem to indicate that there are two species pres- 
ent in the cactus area. The range of the two forms corroborates this 
supposition. There are certain differences between the specimens, but they 
are not sufficient to separate the series into two forms. 



PARASITES OR ENEMIES OF INJURIOUS SPECIES. 45 

Melitara prodenialis Walker. Florida (H. G. Hubbard) ; New Jersey (J. B. 

Smith) ; Biloxi, Miss., September (W. W. Tracy). 
Melitara dentata Grote. Trinidad. Colo. (D. Griffiths). 
*Mclitara fernaldialis Hulst. Santa Fe and Albuquerque, N. Mex., and Tucson. 

Ariz. (F. C. Pratt), on Opuntia; Tucson, Ariz. (H. G. Hubbard), on 

Ccrats giganteus. 
Platynota rostrama Walker. Brownsville. Tex.. May (J. P. Mitchell). 

Reared from Opuntia fruit. Reared in Florida by Dyar from Rivinia, Ran- 

dia, and Gnaphaliurn. 
Dyotopasta yumaella Kearfott. Brownsville, Tex. (J. D. Mitchell) and Arizona. 

Breeds in fruit of Opuntia. 
Marmara opuntiella Busck. At the following localities in Texas: Corpus 

Christi, Brownsville (J. D. Mitchell), San Antonio, Kerrville (F. C. Pratt), 

Marble Falls, New Braunfels (D. Griffiths). Mines beneath epidermis of 

joints. 

IIYMENOrTERA. 

Polistcs rubiginosm Lepeletier. Corpus Christi, Tex.. August (J. I>. Mitchell). 

This and the following species feed as adults on cracked fruit and some- 
times on sound fruit of Opuntia. 

* Polistes flams Cresson. Arizona (H. G. Hubbard). 

Polish v texanus Cresson. Alice. Brownsville, Corpus Christi, Tex., October 
(J. D. Mitchell) : San Antonio, Tex. (F. C. Pratt). 

DIPTERA. 

Ceddomyia opuntiw Felt. Beared in New York from joints of a European 

Opuntia (O. banburjana) and also from a West Indian species. 
Asphondylia opuntia} Felt. Los Angeles, Cal., April (I). Griffiths): Ash Fork, 
Ariz., May (I). Griffiths); Organ Mountains. N. Mex.. January (D. Grif- 
fiths) ; Sinton. Victoria, Kennedy. Corpus Christi. Brownsville, Hondo, 
Cotulla, and Hallettsville. Tex. (J. D. Mitchell) ; Beeville, Tex., March 
(F. C. Pratt) : San Luis Potosi, Mex. (D. Griffiths). 
Breeds in fruit of Opuntia. 
Asphondylia betheli Cockerel]. Colorado. 

In fruit of Opuntia. 
Asphondylia arimonensis Felt. Arizona. 

Reared from "enlargement of prickly pear." 

PARASITES OR ENEMIES OF THE INJURIOUS SPECIES. 
IIEMIPTERA. 

* 8mea raptoria Stal. Tucson, Ariz. 

* Diplodus luridus Stal. Tucson, Ariz. 

COLEOPTERA. 

Exochomus la tin soul its Casey. Corpus Christi. Seguin. San Antonio. Tex.. 

March, October (F. C. Pratt); Cotulla and Beeville, Tex.. April (J. D. 

Mitchell). 
Exochomus marginipermis Le Conte. Corpus Christi. Hondo, Tex. (J. D. 

Mitchell) ; Seguin, Tex.. October (F. C. Pratt). 
Hippodaniia convergent Guerin. Los Angeles, Cal., June (F. C. Pratt). 
Feeds on aphides on Opuntia. 



46 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Cycloneda tnunda Say. Hondo, Tex., April (J. D. Mitchell). 
Chilocorus cacti Linnaeus. Durango, Mex., November (F. C. Bishopp). 
Hyperaspis trifitrcata Schfeffer. Hebbronville, Falfurrias, Floresville, Corpus 

Christi, Victoria, San Diego, Tex., May to August (J. D. Mitchell) ; Seguin, 

Alice, San Antonio, Kerrville, Tex. (F. C. Pratt) ; Durango, Mex. (F. C. 

Bishopp). 
Hyperaspis omenta Le Conte. Mesilla Park, N. Mex., June (D. Griffiths) ; 

Brewster County, Tex. (R. A. Cushrnan) ; El Paso, Tex., August (F. C. 

Pratt). 
Seym n us loewU Mulsant. Brownsville, Tex., March (F. C. Pratt) ; Aguas- 

calientes, Mex., December (F. C. Bishopp). 
Scymnus hornii Gorham. Aguascalientes, Mex., December (E. A. Schwarz and 

F. C. Bishopp). The nine preceding species (except Hippodamia com- 

vergens) are enemies of Dactylopius confusus. 
Bothrideres cactophagi Schwarz. Enemy of Cactophagus validus. 
Trichodes bibaltcatus Le Conte. Cotulla, Tex., May (J. D. Mitchell) ; Dallas, 

Tex., May (F. C. Pratt). 

Feeds upon Melitara and other insects. 
Hydnocera pubcscens Le Conte. Victoria, Tex., May (R. A. Cushman). 
Feeds upon various cactus species. 

LEPIDOPTERA. 

Lcetilia eoccidirora Comstock. Cotulla, Tex., October. 

Enems r of Dactylopius confusus. 
Zophodia dilatifasciella Ragonot. San Antonio, Tex., June (D. Griffiths) ; 
Brown and Young Counties, Tex. (J. D. Mitchell). 

Feeding on Dactylopius confusus. 
Saluria ardiferella Hulst. Mesilla Park, N. Mex., June. 

Feeds upon Dactylopius confusus. 

HYMENOPTERA. 

Mcsostenus thoracicus Cresson. Corpus Christi, Tex., March (F. C. Pratt). 

Probable parasite of Melitara spp. 
Eiphosoma texana Cresson. 

Parasite of Mimorista flavidisiimalis Grote. 
Eurgtoma sp. D'Hanis, Tex., May (J. D. Mitchell). 
Clielonus laticinctus Cresson. Trinidad, Colo., August. 

Parasite of Melitara dentata Grote. 
Apantelcs (Pseudapanteles) sp. Corpus Christi, Tex.. April (W. D. Pierce). 
At Opuntia liudheinicri. 

Possible parasite of Melitara. 
Apantelcs sp. Victoria, Tex., September (J. D. Mitchell). 

Possible parasite of Melitara. 

DIPTERA. 

Phorocera comstocli Williston. Victoria, Tex., October (J. D. Mitchell) ; San 
Antonio, Cotulla, Corpus Christi, Tex., October (F. C. Pratt). 
Parasite of Melitara. 
Drosophila punctulata Loew. San Antonio, Tex., April. May (D. Griffiths) ; 
Victoria, Tex., April, December (J. D. Mitchell) : Brownsville, Tex., March 
(F. C. Pratt). 
Feeds upon Dactylopius confusus. 



SCAVENGERS. 47 

Drosophila ampelophila Loew. Berkeley. Cal., June (D. Griffiths). 

Feeds upon Dactylopius vonfusu-i. 
Lcucopis hclla Loew. San Antonio, Tex., May (D. Griffiths) ; San Diego and 
San Bernardino, Cal. 

Enemy of Dactylopius confusus. 
Lcucopis oellula Williston. Texas, New Mexico, and Mexico. 

Enemy of Dactylopius confusus. 

SCAVENGERS. 
COLEOPTERA. 

*Megasternum ccrei Sehwarz. 

*Dactylosternum cacti Be Conte. 

*Pelosoma capillosum Le Conte. " 

*Eumicru8 lucanus Horn. 

*Tyrus clongatus Brendel. 

*Melba puncticollis Be Conte. 

*Falagria sp. 

% Homalota sp. 

Alcochara sp. Aguascalientes, Mex.. December (E. A. Sehwarz and F. C. 

Bishopp). 
Mascochara valida Be Conte. Beared by Coquillett from puparium of Copes- 

ti/lum marginatum Say in Opuntia engelmanni at Bos Angeles, Cal. 
*Mascochara semivelutina Solsky. 
* Mascochara spacella Sharp. 
■'Mascochara pubcritla Casey. 
Uaseochara sp. Arizona, June (F. C. Pratt). 
*Aphelogl08sa rufipennis Casey. 
♦Aleocharine, genus unknown. 
*OUgota sp. 

*Xanthopygus cacti Horn. 
Belonuchu8 ephvppiatus Say. 
Bclonuclius xanthomelas Solsky. Aguascalientes, Mex., December (E. A. 

Sehwarz and F. C. Bishopp). Victoria and Hondo, Tex., December (J. D. 

Mitchell). 
*Xantholinus dimidiatus Be Conte. 
*Lithocharis tahacina Casey. 
Tacliinodcrus grandis Sharp. Aguascalientes, Mex., December (E. A. Sehwarz 

and F. C. Bishopp). 
*Erchomus punctipennis Be Conte. 
*Erchom us convexus Erichson. Aguascalientes, Mex., December (E. A. Sehwarz 

and F. C. Bishopp). 
*Physetoporu8 grossulus Be Conte. 
Leptochirus cdax Sharp. Aguascalientes. Mex., December (E. A. Sehwarz and 

F. C. Bishopp). 
*Omalittm cacti Sehwarz. 
*Trichopteryx sp. 
*-E phi biennis cactophilus Sehwarz. 

Attagams piceus Olivier. D'Hanis and Encinal, Tex., May (J. D. Mitchell). 
*Atiagenu8 hornii Jayne. 

Carcinops sp. Aguascalientes, Mex., December (F. C. Bishopp). 
Hololcpta cacti Be Conte. San Antonio, Sabinal, and Hondo. Tex., May (F. C. 

Pratt) ; Victoria, Cotulla, Corpus Christi, Baredo, Tex. (J. D. Mitche.ll).. 



48 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

*Hololepta vicina Le Conte. 

Hololepta yucateca Marseul. Aguascalientes, Mex., December (E. A. Schwarz 

and F. C. Bishopp). According to Mr. E. A. Schwarz this species follows 

the attack of other species in Cereus and is of some importance in this 

connection. 
Hololepta strigicolle Marseul. Mexico (Duges). 
*Paromalus opuntice Le Conte. ' 
*Paromalus consors Le Conte. 
*Paromalus gilensis Le Conte. 
Paromalus' sp. Aguascalientes, Mex. 

Saprinus pennsylvanicus Paykull. Cotulla, Tex., May (F. C. Pratt). 
Terapus mniszechi Marseul (E. Duges), Mexico. Although recorded by Duges 

as a cactus insect Mr. Schwarz considers it strictly myrmecophilous. 
*Acritus arizonce Horn. 
Camptodes cacti Duges. 

This is a manuscript name. The species may be C. heterocheilus Sharp. 

Mexico. 
*Holoparamecit8 paciflcus Le Conte. 
*AUndria teres Melsheimer. 

Smicrips hypocoproides Reitter. Corpus Christi, Tex., March (W. 1). Pierce). 
Hyporhagus opuntice Horn. On Opuntia in Arizona (E. A. Schwarz and F. C. 

Bishopp). 
Hyporhagus texanus Linell. San Diego, Tex., in decaying Opuntia engelmanni 

(E. A. Schwarz) ; Encinal and Hondo, Tex. (J. D. Mitchell). 
Brachytarsus sp. Brownsville, Tex., March (C. R. Jones and F. C. Pratt). 

DIPTERA. 

*Ceratopogon sp. Tucson, Ariz. 

*8catopse sp. Tucson, Ariz. 

Hermetia chrysopila Loew. San Antonio, Dallas, Encinal, Tex. (J. D. Mitchell 

and F. C. Pratt) ; Los Angeles, Cal., September (F. C. Pratt). 
Hermetia huntcri Coquillett. Hondo, Encinal, Cotulla, Tex., May to October 

(F. C. Pratt and J. D. Mitchell). 
Cyphomyia scliacffcri Coquillett. Dallas, Tex., June. 
Microdon globosus Fabricius. Dallas, Tex., May (C. R. Jones). 
Vausigaster unimaculata Townseud. Cotulla, San Antonio, Tex., April (F. C. 

Pratt) ; Victoria, Tex. (J. D. Mitchell). 
Reared from Opuntia. 
T'olucella pusilla Macquart. Various Texas localities: Victoria and Tivoli 

(J. D. Mitchell) : Dallas, Corpus Christi. Cotulla, Beeville, San Antonio 

(F. C. Pratt). 
Volvcella fasciata Macquart. New Braunfels, Denton, Dallas, Tex., May (F. C. 

Pratt); Victoria, Tex., May (J. D. Mitchell); New Jersey (J. B. Smith). 
*Volucclla avida Osten Sacken. Tucson, Ariz., December. In Opuntia fulgida 

and Cereus giganteus. (See Psyche, May, 1S99.) Cotulla and San An- 
tonio, Tex. (J. D. Mitchell) ; Encinal, Tex., April to June (F. C. Pratt). 
Volucella esuriens Fabricius. At Texas localities below: Cotulla, Kerrville, 

Hebbronville, S;m Diego (F. C. Pratt) ; Live Oak County, San Antonio, 

Alice, Corpus Christi (J. D. Mitchell), March to May. 
Copestylurn marginatum Say. San Antonio, Falfurrias, Mathis. Live Oak 

County, Kerrville, Encinal. Cotulla, Hondo, Dallas, Tex. (various localities 

by J. D. Mitchell and F. C. Pratt) ; Los Angeles and Riverside, Cal. (F. C. 

Pratt). 



SPECIES MERELY FREQUENTING FLOWERS. 49 

Hilarella decens Townsend. Albuquerque, N. Mex., June (F. C. Pratt). 

Relicobia quadrisetosa Coquillett. Corpus Christi, Tex., March (F. C. Pratt). 

Musca domestica Linnaeus. San Luis Potosi, Mex., June (Rose). 
In decaying fruit. 

Phorbla fnsciccps Zetterstedt. Riverside, Cal., May (D. Griffiths). 

Sapromyza vulgaris Fitch. Riverside, Cal., May (D. Griffiths). 

Rivcllia sp. (?) Corpus Christi and San Antonio, Tex. (F. C. Pratt), March to 
June. 

*Limosma sp. Tucson, Ariz. 

Stictomyia longicornis P.igot. Generally distributed in Texas and Mexico. 
Taken at the following localities in Texas: Victoria. Encinal, Hondo, 
D'Hanis, Tivoli, San Diego, Kingsville, Corpus Christi (J. D. Mitchell) ; 
Sabinal. Kerrville, San Antonio (F. C. Pratt); Brownsville (D. Griffiths), 
March to November. In Mexico at Durango, December (F. C. Bishopp and 

E. A. Schwa rz). 

*Nerius fluvifrons Bigot. Tucson, Ariz. 

SPECIES WHICH MERELY FREQUENT THE FLOWERS. 
COLEOPTKKA. 

Carpophilus palUpennis Say. San Antonio, Encinal, Hondo. D'Hanis, Corpus 
Christi, Tex., May (J. D. Mitchell) ; Dallas, Tex. (F. C. Pratt) ; Los 
Angeles, Cal. (F. C. Pratt), June; San Pedro and Riverside, Cal., May 
(D. Griffiths). 

Aemceodera tiihitliix Fabricius. D'Hanis, Tex., May (J. D. Mitchell) ; Zavalla 
County, Tex.. May (W. I >. Hunter and F. C. Pratt ). 

Acmceodera quadrivittata Horn. El Paso, Tex., August (F. C. Pratt). 

Acnweodera pidchella Herbst. Zavalla County, Tex., May (W. D. Hunter and 

F. C. Pratt). 

'"J. ycaina discoidalis Horn. Arizona. 

Chauliognathus scutellaris Le Conte. D'Hanis, Tex., April (J. D. Mitchell). 

Li8trus sp. Zavalla County, Tex.. May (W. D. Hunter and F. C. Pratt); 

Brownsville, Tex., April (C. R. Jones and F. C. Pratt). 
Euphoria kernii Haldeman. Encinal, San Antonio, and Zavalla County. Tex.. 

May (F. C. Pratt and D. Griffiths) ; Hondo. D'Hanis, and Brownsville, Tex. 

(J. D. Mitchell). 
Colaspoides macrocephalus Schaeffer. D'Hanis. Tex., May (J. D. Mitchell). 
Nodonota tritstis Olivier. D'Hinis. Tex.. May (J. D. Mitchell). 
Leptinotarsa haldemani Rogers. Victoria. Tex., May (J. D. Mitchell). 

Under Opuntia. 
Chrysomela auripennis Say. Victoria, Tex., May (J. D. Mitchell). 
Luperodes brunneus Crotch. Victoria, Tex.. April (J. D. Mitchell). 
Eupogonius vestitus Say (?): Victoria. Tex.. May (J. D. Mitchell). 
Diabrotica t2-punctata Olivier. Los Angeles. Cal., June (F. C. Pratt). 
Phyllotreta pusilla Horn. D'Hanis, Tex.. April (J. D. Mitchell). 
Bruchus sp. Aguascalientes, Mex.. December (E. A. Schwarz and F. C. 

Bishopp) ; Tucson. Ariz.. May (F. C. Pratt). 
Epicauta trivhrus Pallas. Hondo and D'Hanis, Tex... May (J. D. Mitchell). 

IlYMF.XOrTF.UA. 

Ghrysis sp. Victoria. Tex., April ( R. A. Cushmam. 
WaUctus sp. Los Angeles. Cal., June (F. C- Pratt). 

50075°— Bull. 113—12 4 



50 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Dialictus occidentalis Crawford.. Flagstaff, Ariz., June (F. C. Pratt). 

At Echinocereus. 
Augochlora neglectula Cockerell. New Mexico. At Echinocactus wlsliseni 

(T. D. A. Cockerell). 
Agapostemon tenants Cresson. New Mexico. At Cereus polyacanthus and G. 

pendlerif (T. D. A. Cockerell) ; Flagstaff, Ariz.. June (F.<C. Pratt). 
Perdita megacephala Cresson. Hondo, Tex., April (J. D. Mitchell). 
Ashmeadiella cactorum Cockerell. Santa Fe, N. Mex., on Cactus radiosus 

neomexicanus (Eng.) (T. D. A. Cockerell). 
Ashmeadiella opuntiw Cockerell. New Mexico, on Opuntia (T. D. A. Cockerell). 
Ashmeadiella echinocerei Cockerell. Flagstaff, Ariz., at Echinocereus sp 

(F.C.Pratt). 
Heriades gracilior Cockerell. New Mexico, on Opuntia (T. D. A. Cockerell). 
Lithurgus ecMnocacti Cockerell. New Mexico, on Echinocactus wislizeni 

(T. D. A. Cockerell). 
Lithurgus apicalis opuntice Cockerell. New Mexico. At Opuntia a rborescens 

(T. D. A. Cockerell) ; Za valla County and Sabinal, Tex., and Tucson, Ariz. 

(F.C.Pratt). 
Megachile populi Cockerell (Syn. : M. opuntiarum Cockerell, fide Cockerell). 

Colorado (T. D. A. Cockerell). 
Megachile sidalcece Cockerell. New Mexico. 

On Opuntia cngclmanni (T. D. A. Cockerell). 
Melissodes pallidicincta Cockerell. Colorado (T. D. A. Cockerell). 
Melissodes opuntiella Cockerell. Brownsville, Tex. (F. C. Pratt) ; Hondo, Tex. 

(J. D. Mitchell). 
Diadasia australis Cresson. New Mexico and Colorado, on Opuntia arborescens 

(T. D. A. Cockerell) ; Cotulla, Hondo, D'Hanis, and Za valla County, Tex., 

April (F.C.Pratt). 
D. australis opuntiw Cockerell. Southern California, on Opuntia litloralis 

(Eng.) (T. D. A. Cockerell) ; Los Angeles, Cal.. June (F. C. Pratt). 
Diadasia australis rinconis (Cockerell). New Mexico. Opuntia cngelmanni 

and 0. arborescens (T. D. A. Cockerell); Runge, Zavalla County, and 

Brownsville, Tex., March (F. C. Pratt); Cotulla. Tex.. April (J. D. 

Mitchell), on 0. leptocaulis and O. lindheimeri; Los Angeles', Cal. (F. C. 

Pratt). 
Diadasia piercei Cockerell. Beeville, Tex. (C. L. Marlatt). 
Diadasia bituberculata Cresson. Los Angeles, Cal. 

DIPTERA. 

Mesogramma marginata Say. Hondo. Tex.. April (J. D. Mitchell). 

SPECIES INCIDENTALLY ASSOCIATED WITH THE PLANT. 

OKTHOPTERA. 

Spongophora apicidentata Caudell. Aguascalientes, Mexico, December (F. C. 

Bishopp). 
::: Spongophora brunncipennis Serville. Tucson. Ariz. 
Dichromorpha viridis Sr-udder. Laredo. Tex., May (J. D. Mitchell). 
Dichopetala brevihastata Scudder. Alice, Corpus Christi, and Maverick County, 

Tex., May (J. D. Mitchell and F. C. Pratt). 
Dichopetala emarginata Brunner. Bebbronville, Tex., May (J. D. Mitchell). 
Dichopetala sp. Enclnal, Tex., April. 



SPECIES INCIDENTALLY ASSOCIATED WITH PLANT. 51 

Stipator nigromarginata Caudell. Corpus Christi, Tex. (J. D. Mitchell) ; Alice, 

Encinal, and Maverick County, Tex. (J. D. Mitchell). 
Stipator haldemanni Girard. San Antonio, Tex., April (W. I). Hunter and 

F. C. Pratt). 
Stipator mitohelli Caudell. Alice and Hondo, Tex., April (J. D. Mitchell). 
Stipator pratti Caudell. Alice, Tex.. August (J. D. Mitchell). 
Stipator grandis Rehn. Corpus Christi. Tex.. August (J. I). Mitchell). 
Rehnia spinosa Caudell. Cotulla, Encinal, and Hondo. Tex.. May ( F. ( '. Pratt) ; 

Maverick County and Hebhronville, Tex. (J. D. Mitchell). 
Feeding on petal of Opuntia. 

HEMIPTERA. 

*Brochymena ooscura Herrich-Schacffor. San Antonio, Tex., November (J. D. 

Mitchell); Tucson, Ariz. (II. G. Hubbard). 
Anasa tristis Say. Sabinal, Tex., December (F. C. Pratt). 

Under Opuntia. 
Nysius ericce Schilling (Syn. : angustatus Dhler). San Antonio, Tex.. June 

(E. S. Tucker). 
Ligyrocort8 pseudoherwus Barber. San Antonio, Tex.. November (J. D. 
Mitchell). 

Under Opuntia. 
Tempyra biguttula Stal. D'Hanis, Tex., April i J. D. Mitchell). 
Cnemodus mavortius Say. Sabinal, Tex.. December i F. C. Pratt). 

Under Opuntia. 
Lygceus abulus Distant. San Antonio. Tex.. September (J. D. Mitchell). 
Under Opuntia 

COLEOPTERA. 

Pasimachus californicas Chaudoir. Encinal, Tex., April (J. D. Mitchell). 

Pasimactius depressus Fabricius. San Antonio and Cotulla, Tex. (F. C. Pratt). 

Diccelus costatus Lee. Encinal, Tex.. April (J. D. Mitchell). 

Discodcnis impotent Ee Conte. Hondo, Tex., June (J. D. Mitchell). 

Cercyon sp. Aguascalientes, Mexico, December ( F. ('. Bishopp). 

Rhagodera sp. Encinal, Tex., April (J. D. Mitchell). 

*Ditoma gracilis Sharp. 

*Dito»ia sulcata Ee Conte. 

*Bothrideres denticollis Duges, MS. Mexico. 

Agrypnus sallei Ee Conte. Cotulla. Tex., May (J. D. Mitchell). 

Vhalcolepidius viridipiUs Say. D'Hanis, Tex., May (J. 1). Mitchell). 

Dijilnta.ris truncatula Ee Conte. Encinal, Tex.. May (J. D. Mitchell). 

Phileurus cribrosus Ee Conte. Encinal and Hondo. Tex.. April i J. D. Mitchell). 

Ataxia crypta Say. Hondo, Tex., March (J. D. Mitchell). 

Triorophus nodiceps Ee Conte. Encinal and Cotulla. Tex.. May (J. D. Mitchell). 

Eurymetopon muricatulum Casey. Tucson. Ariz.. May i F. <\ Pratt). 

Emmenastus texanus Ee Conte. Encinal and Cotulla, Tex., May (J. D. 

Mitchell). 
Xoscrus emarginatu8 Horn. Hondo, Tex., May (J. D. Mitchell). 
Centrioptera variolosa Horn. Tucson, Ariz., May (F. C. Pratt E 
Centrioptera infausta Le Conte. Cotulla, Tex. (J. D. Mitchell). Under fallen 

Opuntia leaves. Encinal, Tex.. May. 
Eleod&s tricostata Say. Encinal, Tex., May (J. D. Mitchell). 
Elcodcs tejcana Le Conte. Oakville, Tex., December (J. D. Mitchell). 



52 PRINCIPAL CACTUS INSECTS OP UNITED STATES. 

Eleodes ventricosa Le Conte. Hondo, Tex., November (F. C. Pratt). 

Eleodes armata Le Conte. Tucson, Ariz., May (F. C. Pratt). 

Eleodes carbonaria Say. Tucson, Ariz., May (F. C. Pratt) ; Cotulia, Tex. (J. D. 

Mitchell). 
Eleodes carbonaria var. soror Le Conte. Cotulla, Tex. (J. D. Mitchell). 
Anthicux infemus La Ferte-Senectere. Mexico. 
Blapstinus pratensis Le Conte. Hondo, Corpus Christi, Encinal, Cotulla, Tex., 

March to November (J. D. Mitchell) ; Hondo, Tex., November (F. C. 

Pratt). 
*Ulosonia marginata Le Conte. 
*Cyn<BUs angustus Le Conte. 

Helops farcins Le Conte. Hondo, Tex., May (J. D. Mitchell). 
Othnius senecionis Champion. Durango, Mexico, November (F. C. Bishopp) ; 

Aguascalientes, Mex., December (F. C. Bishopp) ; Texas (E. A. Schwarz). 
Compsus auricephalus Say. Hondo, Tex., April (J. D. Mitchell). 
Coleocerus marmoratus Say. D'Hanis, Tex., May (J. D. Mitchell). 
Smicromj.r spretus Dietz. San Antonio, Tex., June (J. C. Crawford). 

On Opuntia. 
Calandra remota Sharp. " Occurs commonly in the stems of banana and prickly 

pear near Honolulu." (Mem. Coleoptera Hawaiian Islands, p. 1S3.) 
*Apotrepus densicollis Casey. 
*Cossonus hubbardi Schwarz. 

LEPIDOPTERA. 

Kricogonia Igsidc Godart. Encinal, Tex.. May (J. D. Mitchell). 
Pontia protodice Boisduval. Encinal. Tex.. April (J. D. Mitchell). 
Campometra impartialis Harvey. Cotulla, Tex., April (J. D. Mitchell). Pupa 

found under dead Opuntia joints. 
Lineodes Integra Zeller. San Antonio, Tex., September. 
On Opuntia. 
" I bred this on Solanacese." — H. G. Dyar. 

HYMENOPTEIiA. 

Stomatocera rubra Ashmead. Corpus Christi. Tex.. April (F. C. Pratt). 
*Pachycondyla harpax F. Smith. Hondo, Tex., May (J. D. Mitchell). 

Under dead Opuntia leaves. 
Neoponera villosa F. Smith. Falfurrias, Tex., April (J. D. Mitchell). 

Nesting in leaves of dead cacti. 
Odontomachus darns Roger (?). Hondo, Tex., June (J. D. Mitchell). 

Crawling under dead Opuntia. 
Pseudomyrma brunnea F. Smith. Aguascalientes, Mex., December (F. C. 

Bishopp) ; Corpus Christi, Tex. (F. C. Pratt). 
PheMole sp. Los Angeles, Cal., June (F. C. Pratt). 

Tuder decaying Opuntia. carrying dipterous larvae. 
Cremastogaster lineolata Say. Hondo, Tex., May (J. D. Mitchell) 

Under dead Opuntia leaves. 
Cremastogaster sp. Tucson, Ariz., May (F. C. Pratt). 

Attending aphis on Opuntia versicolor and O. fulgida. 
Leptothorax sp. Victoria, Tex., April (J. I). Mitchell). 

Nesting in green fruit of Opuntia. 
Dorymyrmex pyramicus Roger var. flavus McCook. Los Angeles, Cal., June 
(F. C. Pratt). 

On Opuntia fruit. 



BIBLIOGRAPHY. 53 

Iridomyrmcx analis Ernest Andre. El Paso, Tex., May (F. C. Pratt), in 
Opuntia bloom; Tucson, Ariz., May (F. C. Pratt), attending aphis on 
Opuntia versicolor, <). engelmonni, and O. fulgida. 
Forelius maccooki Forel. Laredo, Tex., August (J. D. Mitchell). 

Eating Opuntia fruit opened by some other insect. 
Prenolepis viridxht Nylander, subsp. melanderi Wheeler. Victoria, Tex., March 
(J. D. Mitchell). 
In green Opuntia fruit. 
Formica subpolita Mayr, var. Flagstaff, Ariz.. June (F. C. Pratt), 

Attending aphis on Echinocereus. 
Myrmecocystus melliger Forel, var. Brownsville, Tex.. April (R. A. rush- 
man), on Opuntia; Hondo, Tex., May (J. D. Mitchell), under dead leaves 
of Opuntia; Albuquerque, N. Mex., June ( ' F. C. Pratt), on Opuntia 
arborescens. 
Camponotus maculatus vicinus Mayr, var. nitidiventris Emery. Albuquerque, 
N. Mex., May (F. C. Pratt). 
On Opuntia arborescens. 
Camponotus sp. Bee County, Tex., May (J. D. Mitchell). 

Nest in root hole of dead Opuntia. 
PycnomutiUa texana Blake. Hondo. Tex., April (J. D. Mitchell). 
Da8ymutilla orcus Cresson. Corpus Christi, Tex., August (J. D. Mitchell). 
Paratiphia sp. Tucson, Ariz., May. , 

Compsomeris .'/-notatti Fabricius. Victoria, Tex., April (H. P. Wood). 
Odynerus clusmus Cresson. San Diego, Tex., April (F. C. Pratt). 
Euglossa surinamensis Linnaeus. Brownsville, Tex., March (F. C. Pratt). 

On O. lindheimeri. 
Eiicirhi sp. 

DIPTERA. 

Atomosia pueUa Wiedemann. D'Hanis, Tex.. May (J. D. Mitchell). 
Epricromyia floridensis Townsend. " Pratt-Cactus in winter." 
Notogramma stigma Fabricius. San Antonio, Tex., June (F. C. Pratt). 
Epiplatea scutellata Wiedemann. Corpns Christi, Tex., March (F. C. Pratt) ; 

San Antonio, Tex., March (F. C. Pratt). 
Chlorops quinquepunctata Loew. Los Angeles, Cal., June (F. C. Pratt). 
Oscinis coxendix Fitch. Reared at Washington, D. C, from material from 

unknown locality. * 

Note. — In Insect Life, vol. 3, p. 402, will be found a note on injury to MammiUarin 
phello8perma by undetermined sowbugs. Hubbard recorded two species of Gainasidaj 
and two of Pseudoscorpionidw from tbe pulp of Ccreus giganteus. 

BIBLIOGRAPHY OF CACTUS INSECTS. 

This bibliography is intended to be complete in so far as the 
important records of the occurrence of insects on cactus are con- 
cerned. It does not include, however, the numerous references to 
the cochineal insect which are scattered throughout the general lit- 
erature of entomology and many trade journals, although several of 
the more important special articles on this insect have been admitted. 
In the paper by De Xobrega will be found many references to older 
accounts of the cochineal insect. 

1811. Humboldt, A. von. — Political essay on the kingdom of new Spain. 
Translation by John Black. London. 

Full account of the cocbineal industry in Central America. 



54 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

1S49. de Nobrega, Gerardo Jose.^Oii the cultivation of cochineal. <Pharina- 
ceutical Journal, vol. 8, pp. 342-348, 1 fig. 

Covers cultivation of the nopal, rearing the insect, and methods of killing 
the cochineal and preparing it for sale. 

1855. .Martins, Theodor. — Culture of the cochineal in the Canary Islands, 

< Pharmaceutical Journal, vol. 14, pp. 553-556. 
1876. Uhler, P. R. — List of Heiniptera of the region west of the Mississippi, 
including those collected during the Hayden explorations of 1903. 
<P.ul. IT. S. Geol. Survey (2) No. 5, vol. 1, pp. 209-361. 
1S77. Popenoe. E. A. — A list, of Kansas Coleoptera. <Trans. Kans. Acad. 
Sci., vol. 5, pp. 21-40. 

Moneilema annulatum Say on Opuntia in Kansas. 

1878. Popenoe, E. A. — Additions to the catalogue of Kansas Coleoptera. 
<Trans. Kans. Acad. Sci., vol. 6, pp. 77-S6. 

Moneilema semipunctatvm Le Conte on Opuntia in Kansas. 
1883. Blanchard, Raphael. — Les coccide utiles. <Bul. Soc. Zool. France, vol. 
7, pp. 1-117. 

An excellent account of the cochineal insect is to be found on pages 70-90. 

1886. Duges, Eugene. — Metamorphoses de quelques Coleopteres Mexicains. 
<Ann. Soc. Ent. Belg., vol. 21, pp. 26-45, Pis. I-III. 

Describes and figures larva and pupa of Moneilema variolare Thomson, 
and Cactophagus (Sphenopliorus) spinolce Gyllenhal. Notes on breeding in 
Opuntia. 

1888. Riley, C. V.— The food habits of North American Calandridre. <Ins. 

Life, vol. 1, p. 199. 

Mentions Cactophagus validus Le Conte. 

1SS9. Horn. H. G.— (No title.) <Ins. Life, vol. 2, p. 162. 

Note presented by E. A. Schwarz on Caenopwus palmeri, the immature stages 
of which were found in stems of Opuntia bernardina. 

1889. Riley, C. V. — Notes on the cochineal insect <Ins. Life, vol. 1, pp. 

258-259. 

Rearing of predators, Leucopis bellula Williston, and DrosopJiiJa quinaria 
Loew. Also breeding of Dakruma coccidivora (=Lcetilia coccidivora Com- 
stock). 

1891. Coquillett, D. W. — Another parasitic rove beetle. <Ins. Life, vol. 3, 
pp. 318-319. 

Maseochara valida, parasite upon puparium of Copestylum marginatum Say 
in 0. engelmanni, California. 

1891. Riley, C. V.— (No title.) <Can. Ent., vol. 23, p. 256. 

Breeding of Melitara prodenialis Walker (Megaphycis bollii) from Opuntia 
" fruit " sent by Mrs. Mary Treat from Florida in 1877. 

1891. Riley. C. V., and L. O. Howard. — Sowbugs feeding in living plants. 
<Ins. Life, vol. 3. p. 402. 

Sowbugs (not determined) feeding on Mammillaria phellosperma in Cali- 
fornia. 

1891. Smith, J. P..— Habits of Volucella fasciata. <Can. Ent.. vol. 23, pp. 
242-243. 

Breeding of Melitara prodenialis Walker and Volucella fasciata Macquart 
in New Jersey. 

1891. Williston, S. W— (No title.) <En(. News, vol. 2, p. 162. 

Breeding of Copestylum marginatum Say and Volucella fasciata Macquart. 

1892. Kellogg, V. L. — Notes on Melitera (sic) detitata Grote. <Kans. Univ. 

Inst., vol. 1, no. 1. pp. 39-41, 1 pi. 

1893. Rilet, O. V., and L. O. Howard. — Insect injury to cactus plants. <Ins. 

Life, vol. 4, p. 345. 

Chelinidea vittigera Uhler in Harris County, Tex. 



BIBLIOGRAPHY. 55 

1894. Uhler, P. R. — Observations upon the heteropterous Hemiptera of Lower 

California, with description of new species. <Proc. Cal. Acad. Sci., 
ser. 2, vol. 4. pp. 223-295. 

Xnriiia femorata Stal., A", pallidicomis Stal., and CheUnidea vittigera Uhler. 

1S95. Gillette. C. P., and ('. F. Baker. — A preliminary list of the Hemiptera 
of Colorado. <Bnl. 31, Colo. Agr. Exp. Sta. 

1895. Howard. L. O. — A destructive scale insect new to the United States. 

<Ins. Life, vol. 7, p. 430. 

Dactylopius (=P8eudococcu8) oirgatus Cockerel] on " Jaeobo " cactus at 
Brownsville, Tex. 

1S95. HniHARD. H. G. — The oviposition of Militant prodenialis Walk. <I'roc. 
Ent. Soc. Wash., vol. 3, pp. 129-132, figs. 6, 7. 

1896. Marlatt. C. L. — (No title.) <Proe. Ent. Soc. Wash., vol. 4, pp. 44, 45. 

Mentions Lobon hesperiua (=sti/h)i>i(lea picta Uhler) on Opuntia. 

1896. Schwarz, E. A.— (No title.) <Proc. Ent. Soc. Wash., vol. 3. p. 48. 

Mentions as cactus insects Moneilema crassum Le Conic Acalles (=Gcr- 
stwckrria) turbidus Le Conte, .1. noMUs Le Conte, Copestylum marginatum 
Say. and an undescribed ortalid fly which breeds in the stems. 

1897. Cockerell, T. D. A. — The New Mexico bees of the genus Ileriades and a 

new Halictus. <Ann. Mag. Nat. Hist., vol. 20. pp. 135-143. 

Several cactus bees are described. Description of Lithurgus cchinocacti 
Cockerell. 

1S9S. Coquillett, D. W. — On the habits of the Oscinidse and Agromyzidae 
reared at the T T . S. Department of Agriculture. <Bul. 10. Bur. Ent., 
U. S. Dept. Agr., pp. 7P-7!). 

Rearing of Lcucopis belhtla Williston from " larva preying on Coccus cacti/' 
Texas; also from Coccus confusum, New Mexico, and AcuntJiococcus sp., 
Mexico. 

1S9S. Cockerell, T. D. A. — New anil lit tic-known Hymenoptera taken by Prof. 
C. H. T. Townsend and Mr. C. M. Barber in New Mexico in 1898. 
<Ann. Mag. Nat. Hist., vol. 2, pp. 448-457. 

1899. Hudbard. H. G. — Insect fauna of the giant cactus of Arizona. Letters 
from the southwest. <Psyehe, Suppl., May, pp. 1-13. 
Notes on Opuntia spp. are to be found on p. 5. 

1S99. Schwarz, E. A. — Classified list of species observed by H. G. Hubbard 
on the giant cactus. < Psyche, Suppl., May, pp. 13-14. 

1899. Linell. M. L. — Descriptions of some new species of North American 

heteromerus Coleoptera. <Proc. Ent. Soc Wash., vol. 4. pp. 180-185. 
Original description of Hyporhagus texanus from decaying Opuntia engel- 

niatini at San Diego, Tex. 

1900. Cockerell, T. D. A. — The cactus bees; genus Lithurgns. <Am. Nat., 

vol. 34, pp. 4S7-4SS. 

1901. Duges, Eugene. — Catalogo de la coleccion de Coleopteros Mexicanos del 

Museo Nacional. <Cat. Mus. Nac, vol. 5. 2d ed.. pp. i-iv, 1-148, pis. 12. 
"Moneilema Uevithoraf White. En los nopales, Guanajuato." 
1901. Schwabs, E. A.— (No title.) <Proc. Ent. Soc. Wash., vol. 4, pp. 368-369, 
1901. 

"Exhibited pulp of giant cactus with living Cactopinm hubbardi Schwarz, 
indicating that they may live in adult condition for two years." On page 
43t an additional note by Mr. Schwarz shows an increased longevity amount- 
ing to a period of four years. 



56 PRINCIPAL CACTUS INSECTS OP UNITED STATES. 

1902. Dyar, H. G. — Descriptions' of the larvae of some moths from Colorado. 

<Proc. U. S. Nat. Mus., vol. 25, pp. 369-412. 

On page 396 is a description of a larva supposed to be that of Melitara 
junctolineella Hulst. See p 27, antea. 

1903. Fernald, M. E. — A catalogue of the Coccidse of the world. <Bul. 88, 

Mass. Agr. Coll., pp. 360. 

1903. Townsend, C. H. T. — Contribution to a knowledge of the Coleoptera of 
the lower Rio Grande Valley in Texas and Tamaulipas, with biological 
notes and special reference to geographical distribution. <Trans. Tex. 
Acad. Sci., vol. 5, pp. 49-101. 

Acallcs ( = Gcrstceckeria) clathratus Le Conte "very numerous on Opuntia 
leptocaulis, breeding in the ends of the shoots, June 5th. This species kills 
the ends of the shoots of this plant, the grub eating out the inside portion 
and forming a cell in which it transforms." 

1905. Knuth, P., Otto Appel, and Ernest Loew. — Handbuch der Bliitenbiologie, 
Leipzig. 

Pages 262-263 cover Cactacese. The following insect records are made : 
Megachile sidalcew Cockerell on Opuntia engelmanni (Bot. Jahrb., 1901, 
vol. 2, p. 583, New Mexico) ; Diadasia (Eucera) unicornis Cockerell, New 
Mexico; Diadasia unicornis opuntiw Cockerell, Viereck, Proc. Acad. Sci. 
Phila., vol. 54, p. 728, 1902, California. 

1905. Cockerell, T. D. A.— The bees of southern California. <Bul. So. Cal. 

Acad. Sci.. vol. 4, p. 15. 

Diadasia australis opuntiw Cockerell, at blooms of Opuntia littoralis Eng. 

1906. Osborn, Herbert. — Note on food habit of Liotropis contaminatus IJhl. 

<Ent. News, vol. 20. p. 177. 

On fruit of Opuntia fulgida, Arizona; also El Paso, Tex., and Inyo Moun- 
tains, Cal. 

1906. Cockerell, T. D. A. — Descriptions and records of bees, VIII. <Ann. 
Mag. Nat. Hist., vol. 17, pp. 222-230. 
Includes several cactus species. 

1906. Cockerell, T. D. A. — The North American bees of the family Antho- 
phoridse. <Trans. Amer. Ent. Soc, vol. 32, pp. 63-116. 

Melissodes pallidicincta Cockerell, and Diadasia spp. in blooms of Opuntia. 

1906. Cockerell, T. D. A. — The bees of New Mexico. <Trans. Amer. Ent. Soc, 

vol. 32, pp. 289-314. 

Lithurgus apicalis Cresson, L. echinoeacti Cockerell, and Megachile sidalcew 
Cockerell. 

1907. Busck, Aug. — New American Tineina. <Proc. Ent. Soc. Wash., vol. 8, 

pp. 86-99. 

Original description of Marmara opuntiella on OpunHa sp., southern Texas. 

1907. Cockerell, T. D. A. — A gall gnat of the prickly pear cactus. <Can. Ent., 
vol. 39, p. 324. 

Description of Asphondylia betheli Cockerell. 

1907. Pierce, W. D. — On the biologies of the Rhynchophora of North America. 
<Rept. Nebr. St. Bd. Agr., 1906, pp. 249-319, 8 pis. 

Includes notes on Acallcs nobilis Le Conte, A clathratus Le Conte, and 
A. turbidus Le Conte. These species are now placed under Gerstackeria. 



BIBLIOGRAPHY. 57 

190S. Banks. Nathan. — & new Tetranychus. <Proc. Ent. Soc. Wash., vol. 
10, p. 36. 

Original description of T. opuntiw Banks. 

1908. Dyar, H. G. — Description of eleven new North American Pyralidre, with 
notes on a few others. <Proc. Ent. Soc. Wash., vol. 10, p. 113. 

Description of Dicymolomia opuntialis Dyar. 

190S. Felt, E. P.— Studies in Cecidomyiidse, II. <Bul. 124", N. Y. St. Mus., 
pp. 307-422. 

Pages 376-378 contain descriptions of Asphotldylia betheli Cockerell, 
A. opuntiw n. sp., and A. arizoncnsis n. sp. 

1908. Griffiths, David. — The prickly pear as a farm crop. <Bul. 124, Bur. 

Plant Ind., U. S. Dept. Agr. 

i 

Diseases and Tetranychus opuntiw mentioned. 

1909. Coquillett, D. W. — A new stratiomyid from Texas. <Can. Ent., vol. 41, 

p. 212, 1909. 

Description of Hermitiu hunteri Coquillett. 

1909. Essig, E. O. — The genus Pseudococcus in California. <Pomona Journ. 

Ent., vol. 1. no. 2, pp. 35-46, figs. 22-32. 

Description of Pseudococcus obscurus on roots of Opuntia sp., California 
(P. 43). 

1910. Felt, E. P. — Two new Cecidomyiidre. <Ent. News, vol. 21, pp. 10-12. 

Original description of Cecidomyia opuntiw, on Italian and West Indian 
Opuntia in New York Botanical Gardens. 

1911. Pierce, W. D. — Systematic notes and descriptions of some weevils of 

economic or biological importance. <Proc. U. S. Nat. Mus., vol. 42, 
no. 1889. pp. 155-170. 

Contains a systematic treatment of the genus Gerteckeria, with descrip- 
tions of Gcrstwckeria tesseliata, G. alternata, G. opuntiw, G. fasciata, and 
G. cactophaya, all of which are protfcbly cactus insects. 



INDEX. 



Page. 

Acalles clathratus, bibliographic reference 56 

=Gerstseckeria elathrata 56 

nobilis, bibliographic reference 55, 56 

=Gerstxckeria nobilis 56 

turbidus, bibliographic reference 55, 56 

=Gerstxckeria turbida . . . . _ 55, 56 

Acanthococcus sp., bibliographic reference 55 

Acmseodera pulchella frequenting flowers of cactus 49 

quadririttata frequenting flowers of cactus "0 

tubulus frequenting flowers of cactus 49 

Acritus arizonx, scavenger in cactus 48 

Agapostemon texanus frequenting flowers of cactus 50 

Agrypnus sallei incidentally associated with cactus 51 

Aleochara sp., scavenger in cactus 47 

Aleocharine, genus unknown, scavenger in cactus 47 

Alindria teres, scavenger in cactus 48 

Allorhina mutabilis, an injurious cactus insect 35, 43 

Anasa tristis incidentally associated in cactus 51 

Anthicus inferens incidentally associated with cactus 52 

Ant, white. (See Termes flavipes.) 

Apanteles (Pseudapanteles) sp., possible parasite of cactus insect (Melitara). ... 46 

sp., possible parasite of cactus insect (Melitara) 46 

Apantesis arge in list of injurious cactus insects 44 

Apheloglossa rufipennis, scavenger in cactus 47 

Aphis medicagin is, hibernating on Opuntia 25 

in list of injurious cactus insects 41 

sp. on Echinocereus, attended by Formica subpolita 53 

Opuntia versicolor and Opuntia fulgida, attended by Crcmastogaster 

sp 52 

Opuntia engelmanni, and Opuntia fulgida, at- 
tended by Iridomyrmex analis 53 

Apotrepus densicollis incidentally associated with cactus 52 

Arsenate of lead against Chorizagrolis soror 15 

Moneilema crassum 15 

powdered, against Mimorista flavidissimalis 22 

Ashmeadiella cactorum frequenting flowers of cactus 50 

echinocerei frequenting flowers of cactus 50 

opuntix frequenting flowers of cactus 50 

Asphondylia, three species injurious to cactus 13 

Asphondylia arizonensis, bibliographic reference 57 

in list of injurious cactus insects 45 

betheli, bibliographic reference 56, 57 

in list of injurious cactus insects 45 

opuntix, an injurious cactus insect 34, 45 

bibliographic reference 57 

Ataxia crypta included in list of injurious cactus insects 51 

59 



60 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Atomosia puella included in list of injurious cactus insects 53 

Attagenus hornii, scavenger in cactus 47 

piceus, scavenger in cactus 47 

Augochlora neglectula frequenting flowers of cactus 50 

Banana, Calandra remota in stems 52 

Belonurhus ephippiatus, scavenger in cactus 47 

xanthomelas, scavenger in cactus 47 

Blapstinus pratensis incidentally associated with cactus 51 

Bothrideres cactophagi, enemy of cactus insect ( Cactophagus validus) 46 

denticollis incidentally associated with cactus 51 

Brachytarsus sp . , scavenger in cactus 48 

Brochymena obscura incidentally associated with cactus 51 

Bruchus sp. frequenting flowers of cactus 49 

Burning against Chelinidea vittigera 20 

cottony cochineal insect 24 

Melitara junctolineella 28 

Moneilema crassum .• 14-15 

Cactophagus spinolse, bibliographic reference 54 

in list of injurious cactus insects 44 

striatoforatus in list of injurious cactus insects 44 

validus, bibliographic reference 54 

prey of Bothrideres cactophagi 46 

synonym of Cactophagus spinolse 44 

Cactopinus hubbardi, bibliographic reference 55 

in list of injurious cactus insects 44 

Cactus as food for cattle, experiments 10-11 

man 9-11 

cultivation in Texas in 1905 11-12 

dissemination by Moneilema beetles 13-14 

distribution, general 9-11 

food plant of dye-producing cochineal insect 9-10 

giant. (See Cereus giganteus.) 

insects, bibliography 53-57 

historical remarks 11-12 

injurious to Opuntia, in order of importance 13 

list of principal ones in United States 39-53 

number and classification 12-13, 39 

attacking joints 12 

roots and stems 12 

destroying outside of joints 12 

feeding inside joints 12 

in blooms 12 

injuring fruit 12 

plant 12, 39 

of parasites 12, 39 

scavengers 12, 39 

only incidentally associated with plant 12, 39 

visiting flowers 12, 39 

parasites or enemies of injurious species 45-47 

personnel of present investigation 12 

species attacking joints externally 15-25 

internally 25-32 

roots or stems 13-15 



INDEX. 61 

Page. 

Cactus insects, species incidentally associated with plant 50-53 

injuring blooms 32 

fruit 32-36 

merely frequenting flowers 49-50 

that are scavengers 37-39, 47-49 

relation to cochineal industry 9-11 

"opuntia," food plant of Cactophagus spinolx 44 

Cactus radiosus neomexicanus , flowers frequented by Ashmeadiella cactorum .... 50 

Csenopceus palmeri in list of injurious cactus insects 43 

Calandra remota incidentally associated with cactus 52 

Campometra impartialis incidentally associated with cactus 52 

Camponotus maculatus vicinus var. nitidiventris incidentally associated with 

cactus 53 

sp. incidentally associated with cactus 53 

Camptodes cacti, scavenger in cactus, perhaps = Camptodes heterocheilus 48 

heterocheilus, Camptodes cacti Duges MS perhaps a synonym 48 

Carcinops sp. , scavenger in cactus 47 

Carpophilus pallipennis frequenting flowers of cactus 49 

Cecidomyia opuntix, bibliographic reference 57 

in list of injurious cactus insects 45 

Cecidomyiidse reared from Opuntia 35 

Centrioptera infausta incidentally associated with cactus 51 

variolosa incidentally associated with cactus 51 

Ceratopogon sp. , scavenger in cactus 48 

Cercyon sp. incidentally associated with cactus 51 

Cereus, food plants of Allorhina mutabilis 35, 43 

Cactophagus striatoforatus 44 

Margarodcs sp. (formicarum?) 41 

Narnia femorata 41 

Polistes flavus 36 

Termes flavipes 40 

Hololepta yucateca a scavenger therein 48 

unimportant as forage 11 

Cereus giganteus, food plant of Diaspis echinocacti cacti 12 

Melitara fernaldialis 29 

insect-fauna investigations 11 

insects taken thereon (names preceded by *). . 39, 41, 43, 44, 45, 47-53 

two species of Gamasidse taken from pulp 53 

Pseudoscorpionidse taken from pulp 53 

macrogonus, food plant of Diaspis echinocacti cacti 42 

pendleri (?), flowers frequented by Agapostemon texanus 50 

polyacanihus , flowers frequented by Agapostemon tcxan us 50 

Chalcolepidius riridipilis incidentally associated with cactus 51 

Chauliognathus scateUaris frequenting flowers of cactus -19 

Chelinidea, three species injurious to cactus 13 

Chelinidea sp., an injurious cactus insect 20, 40 

tabulata, an injurious cactus insect 19, 49 

vittigera. an injurious cactus insect 15-17, 40 

bibliographic reference 54, 55 

control of this and allied species 20 

description of stages L8 19 

dimorphism 19 

distribution 17 



62 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Chelinidea vittigera, egg, description 18 

hibernation 19 

injury, nature 16-17 

life history 1S-19 

nymphal stages, description 18-19 

variations 17 

Chelonus laticinctus, parasite of cactus insect ( Melitara dentata) 28, 46 

Chilocorus cacti, enemy of cactus insect (Dactylopius confusus) 24, 46 

Chlorops quinquepunctata incidentally associated with cactus 53 

Chorizagrotis soror, an injurious cactus insect L5, 44 

Chrysis sp. frequenting flowers of cactus 49 

Chrysomela auripennis frequenting flowers of cactus 49 

Cnemodus mavortius incidentally associated with cactus 51 

Coccidae attacking roots and stems of cactus 15 

Coccus (see also Dactylopius) . 

Coccus cacti, bibliographic reference 55 

confusum, bibliographic reference 55 

Cochineal, early history of industry 23, 24 

former extent of industry 9 

insect (see also Dactylopius coccus). 

exports from Canary Islands 9 

not a native of the United States 23 

cottony. (See Dactylopius confusus.) 

Cainopceus palmeri, bibliographic reference ."> 1 

Colaspoides macrocephalus frequenting flowers of cactus 49 

Coleocerus marmoratus incidentally associated with cactus 52 

Compsomeris 4-notata incidentally associated with cactus 53 

Compsus auricephalus incidentally associated with cactus 52 

Copestylum marginatum , an injurious cactus insect 37 

bibliographic references 54, 55 

Maseochara valida reared from puparium 47 

scavenger in cactus 48 

Cornifrons elautalis, an injurious cactus insect 35, 44 

Corythuca deccns in list of injurious cactus insects 41 

Cossonus hubbardi incidentally associated with cactus 52 

Cremastogaster lineolata incidentally associated with cactus 52 

sp., attendant on aphis on Opuntia versicolor and puntia/ulgida . 52 

incidentally associated with cactus 52 

Cutworm. (See Chorizagrotis soror.) 

Cycloneda munda, enemy of cactus insect (Dactylopius confusus) 24, 46 

Cynxus angustus incidentally associated with cactus 52 

( 'ypliomyia schaejferi, scavenger in cactus 48 

Dactylopius (Coccus), near confusus, in list of injurious cactus insects 42 

spp. in list of injurious cactus insects 42 

coccus (see also Cochineal insect). 

in list- of injurious cactus insects 42 

confusus, an injurious cactus insect 13, 23-25, 42 

control 24-25 

enemies 24 

prey of Chilocorus cacti 46 

Cycloneda munda . . -!(> 

Drosophila ampelophila 47 

punctulata 46 



INDEX. 63 

Page. 

Dactylopius confusus, prey of Exochomus latiusculus 45, 46 

margin ipt nnis 45, 46 

Hyperaspis cruenta 46 

trifurcata 46 

Lsetilia coceidivora 16 

Leucopis bclla 47 

bellula 47 

Saluria ardi/erdla 46 

Scymnus hornii -|(J 

loewii 46 

Zophodia dilatifasciella 46 

longifilis=Pseudococeus longispinus 42 

tomentosus, an injurious cactus insect, control L3, 25,42 

virgatus, bibliographic reference 55 

= Pseudococcus virgatus 55 

Dactylosternurn cacti, scavenger in cactus 47 

Dakruma coceidivora, bibliographic reference 54 

=Lxtilia coceidivora 54 

Dasymutilla orcus incidentally associated with cactus 53 

Dendrocoris contaminatus in list of injurious cactus insects 41 

Diabrotica IS-punctata frequenting flowers of cactus 49 

Diadasia australis frequenting flowers of cactus 50 

opuntise, bibliographic reference 56 

frequenting flowers of cactus 50 

rinconis frequenting flowers of cactus 50 

bituberculata frequenting flowers of cactus 50 

picrcei frequenting flowers of cactus 50 

spp., bibliographic reference 56 

unicornis, bibliographic reference 56 

opuntise, bibliographic reference 56 

Dialictus occidental)* frequenting flowers of cactus 50 

Diaspis cacti in list of injurious cactus insects 42 

opuntieola in list of injurious cactus insects 42 

echinocacti in list of injurious cactus insects 42 

cacti, an injurious cactus insect 13, 25, 42 

opuntise in list of injurious cactus insects 42 

Dicselus costatus incidentally associated with cactus 51 

Dichopetala brevihastata incidentally associated with cactus 50 

emarginata incidentally associated with cactus 50 

sp. incidentally associated with cactus 50 

Dichromorphn viridis incidentally associated with cactus 50 

Dictyobia perm utata in list of injurious cactus insects 41 

Dieymolomia julianalis, enemy of Thyridopteryx ephemerseform is 44 

in list of injurious cactus insects 44 

opuntialis, bibliographic reference 57 

in list of injurious cactus insects 44 

Diptodus luridus, enemy of cactus insects 45 

Diplotaxis truncatula incidentally associated with cactus 51 

Discoderus impotens incidentally associated with cactus 51 

Disonycha vcaricom is, an injurious cactus insect 22, 43 

Ditoma gracilis incidentally associated with cactus '. . 51 

sulcata incidentally associated with cactus 51 

Dorymynnex pyramicus var. Jlavus incidentally associated with cactus 52 



64 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Drosophila ampelophila, enemy of cactus insect (Dactylopius confusus) 47 

punctulata, enemy of cactus insect (Dactylopius confusus) 46 

quinaria, bibliographic reference. 54 

Dyotopasta yumaella, an injurious cactus insect 36, 45 

Echinocereus, flowers frequented by Dialictus occidentalis 50 

food plant of aphis 53 

Echinocereus sp., flowers frequented by Ashmeadiella echinocerei 50 

spp., food plants of Sixeonotus luteiceps 41 

Echinocactus ottonis, food plant of Diaspis echinocacti 42 

setipennis, food plant of Gerstseckeria bifasciata 43 

sp. , food plant of Diaspis echinocacti cacti 42 

tenuispinus, food plant of Diaspis echinocacti 42 

wislizeni, flowers frequented by Augochlora neglectula 50 

Lithurgus echinocacti : . 50 

Eiphosoma texana, parasite of cactus insect ( Mimorista fiavidissimalis) 22, 46 

Eleodes armata incidentally associated w ith cactus 52 

carbonaria incidentally associated with cactus 52 

var. soror incidentally associated with cactus 52 

texana incidentally associated with cactus 51 

tricostata incidentally associated with cactus 51 

ventricosa incidentally associated with cactus 52 

Emmenastuc texanus incidentally associated with cactus 51 

Ephistem us cactophilus, scavenger in cactus 47 

Epicauta trichrus frequenting flowers of cactus 49 

Epiplatea scutellata incidentally associated with cactus 53 

Epricromyia fioridensis incidentally associated with cactus 53 

Erchomus convexus, scavenger in cactus 47 

punctipennis, scavenger in cactus 47 

Eriococcus coccineus, an injurious cactus insect 25, 41 

Eucsela sp. incidentally associated with cactus 53 

Eucera unicornis. (See Diadasia unicornis.) 

Euglossa surinamensis incidentally associated with cactus 53 

Eumicrus lucanus, scavenger in cactus 47 

Euphoria kernii frequenting flowers of cactus 32, 49 

Eupogonius vestitus frequenting flowers of cactus 49 

Eurymetopon muricatulum incidentally associated with cactus 51 

Eurytoma sp., parasite of cactus insects 46 

Exochomus latiusculus, enemy of cactus insect (Dactylopius confusus) 24, 45 

marginipennis, enemy of cactus insect (Dactylopius confusus) 24, 45 

Falagria sp., scavenger in cactus 47 

"Fly, droop-winged." (See Stictomyia longicornis .) 

Forelius maccoohi incidentally associated with cactus 53 

Formica subpolita attending aphis on Echinocereus 53 

incidentally associated with cactus 53 

Fungous disease. (See Perisporium sp.) 

Gamasidse taken from pulp of Cereus giganteus 53 

Gasoline torch against Chelinidea vittigera 20 

Melitara junctolineclla 28 

Mimorista fiavidissimalis 22 

Narnia pallidicornis 34 

Stylopidea picta 23 

Gerstseckeria, systematic treatment of genus, bibliographic reference 57 

Gerstseckeria alternata, bibliographic reference 57 

basalis in ] ist of injurious cactus insects 43 



INDEX. 65 

Page. 

Gerstseckeria bi/asdata in list of injurious cactus insects 43 

cactophaga, bibliographic reference 57 

in list of injurious cacl us insects 44 

clathrata, an injurious cactus insect 30, 44 

bibliographic reference 57 

hubbardi in list of injurious cactus insects 43 

on Opuntia vulgaris 30 

nobilis, an injurious cactus insect 30, 43 

opuntise, bibliographic reference 57 

in list of injurious cactus insects 44 

porosa, an injurious cactus insect 29-30, 43 

tessellata, bibliographic reference 57 

turbida in list of injurious cactus insects 44 

(inaphalium, food plant of Pkttynotd rostrana 45 

Hudronema robusta in list of injurious cactus insects 40 

f lul ictus sp. frequenting flowers of cactus 49 

Hand picking against Moneilema crassum 14 

Ilclirobia quadrisetosa, scavenger in cactus 49 

Helops farctus incidentally associated with cactus 52 

lit riades gracilior frequenting flowers of cactus 50 

Hermctia chrysopila, an injurious cactus insect 38-39 

scavenger in cactus 48 

hunteri, an injurious cactus insect e 38-39 

bibliographic reference v . . 57 

scavenger in cactus 48 

Hilarella deems, scavenger in cactus 49 

Ilippodamia convergens, enemy of cactus insects (aphides) 45 

IMolepta cacti, scavenger in cactus 47 

strigicolle, scavenger in cactus 48 

vicina, scavenger in cactus 48 

yucateca, scavenger in cactus 48 

Holoparamecus pacifieus, scavenger in cactus 48 

Homalota sp., scavenger in cactus 47 

Hydnocera pubescens, enemy of cactus insects 46 

Ilyperaspis eruenta, enemy of cactus insect (Dactylopius eonfusus) 24, 46 

trif areata, enemy of cactus insect (Dactylopius eonfusus) 24, 46 

Hyporhagus opuntise, scavenger in cactus 4S 

texanus, bibliographic reference , 55 

scavenger in cactus 48 

Iridomyrmex analis, attendant of aphis on Opuntia versicolor i puntia engelmanni, 

and Opuntia fulgida 53 

incidentally associated with cactus 53 

Kerosene emulsion in control of cottony cochineal insect 24 

Kricogonia lysida incidentally asa >ciated with cactus j 52 

l.:i ti/in coccidivora, enemy of cactus insect (Dactylopius eonfusus) 24,46 

Largus succinctus in list of injurious cactus insects 40 

I.i ■■pidosaphes (Opuntiaspis) philoeoccus in list of injurious cactus insects 42 

Leptinotarsa haldemani frequenting flowers of cactus 49 

Leptochirus edax, scavenger in cactus 47 

Leptothorax sp. incidentally associated with cactus 52 

Leucopis bella, enemy of cactus insect (Dactylopius eonfusus) 47 

bellula, bibliographic reference 54, 56 

enemy of cactus insect (Dactylopius eonfusus) 47 

50975°— Bull. 113—12 5 



66 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Ligyrocoris pseudoherasus incidentally associated with cactus 51 

Lime-sulphur mixture against cottony cochineal insect 24 

Limosina sp., scavenger in cactus 49 

Lineodes Integra incidentally associated with cactus 52 

Liotropis contaminatus, an injurious cactus insect 36, 40 

bibliographic reference 56 

Listrus sp. frequenting flowers of cactus 49 

Litliocharis tabacina, scavenger in cactus 47 

Litliurgtis apicalis, bibliographic reference 56 

opuntise frequenting flowers of cactus 50 

echinocacti, bibliographic reference 55, 56 

frequenting flowers of cactus 50 

Lobos hespcrius, bibliographic reference 55 

=Stylopidea picta 55 

Longevity of larva of Eermetia chrysopila 38-39 

Lopidea cuneata in list of injurious cactus insects 40 

Luperodes brunneus frequenting flowers of cactus 49 

Lycsena discoidalis frequenting flowers of cactus 49 

Lygseus abvhis incidentally associated with cactus 51 

Macrotylus verticalis in list of injurious cactus insects 41 

Mammillaria phellosperma, bibliographic reference 54 

injury by sowbugs 53 

Margarodes sp. (formicarum?) in list of injurious cactus insects 41 

Marmara opuntiella, an injurious cactus insect 13, 31-32, 45 

bibliographic reference 56 

Maseochara puberula, scavenger in cactus 47 

semivelutina, scavenger in cactus 47 

spacella, scavenger in cactus 47 

sp. , scavenger in cactus 47 

valida, bibliographic reference 54 

scavenger in cactus 47 

Megachile opuntiarum= Megachile populi t 50 

populi frequenting flowers of cactus 50 

sidalcex, bibliographic reference 56 

frequenting flowers of cactus 50 

Megaphycis bollii, bibliographic reference 54 

Megasternum cerei, scavenger in cactus -i 7 

Mdba puncticollis, scavenger in cactus 47 

Mclissodes opuntiella frequenting flowers of cactus 50 

pallidicincta, bibliographic reference 56 

frequenting flowers of cactus 50 

Melitara, four species injurious to cactus 13 

host of Phorocera comstochi -1 6 

possible host of Apanteles (Pseudapanteles) sp 46 

sp 16 

prey of Trichodes bibalteatus 46 

Melitara dentata, an injurious cactus insect 28, 45 

bibliographic reference 54 

host of Chelonus lalicinctvs 28, 46 

fernaldialis, an injurious cactus insect 29, 45 

junctolineella, an injurious cactus insect 25-28, 44 

bibliographic reference 56 

control 27-28 



INDEX. 67 

Page. 

Melitara junctolineella, description of immature stages 27 

insect and work 25 

eggs 25 

habits 26 

diversity therein 27 

host of Phorocera comstocH 27 

injury ' 26 

larva, description 27 

pupa , descript ion 27 

prodenialis, an injurious cactus insect L'S-29, 45 

bibliographic references 54, 55 

description of eggs 28-29 

habits of larvae 28-29 

spp., probable hosts of Memstenus thoradcus 46 

Mesogramrna marginata frequenting flowers of cactus 50 

Mesostenus thoradcus, probable parasite of cactus insects (Melitara spp.) 46 

Microdon globosus, scavenger in cactus 48 

Mimorista Jlavidissimalis , adult, description 21 

an injurious cactus insect 13. 20-22, 44 

control 22 

damage effected 21-22 

description 21 

host of Eiphosoma tc.rana 22, 46 

larva, description 21 

most destructive cactus insect within its range 16 

pupa, description 21 

seasonal history 21 

Moneilema, four species injurious to cactus 13 

Moneilema annulatum , bibliographic reference 54 

in list of injurious cactus insects 43 

armatum in list of injurious cactus insects 43 

crassum, bibliographic reference 55 

cocoon -. 14 

in list of injurious cactus insects 43 

Texas 13 

larva, damage to cactus 14-15 

description 14 

pupa 14 

gigas in list of injurious cactus insects 43 

Isevithora.i . bibliographic reference 55 

in list of injurious cactus insects 43 

semipiituiatian. bibliographic reference 54 

in list of injurious cactus insects 43 

sp. in list of injurious cactus insects 43 

spp.. injurious cactus insects. . .: 13-15 

spoliatum in list of injurious cactus insects 43 

ulkei in list of injurious cactus insects 43 

Texas 13 

variolare, bibliographic reference 54 

in list of injurious cactus insects 43 

Ma sea domestica, scavenger in cactus 49 

Myrtnecocystus melliger incidentally associated with cactus 53 

Narnia, four species injurious to cactus 13 



68 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Namia femorata , an injurious cactus insect 34, 41 

bibliographic reference 55 

distribution 34 

inornata, an injurious cactus insect 34, 41 

pallidicornis, an injurious cactus insecl 32-33, 41 

bibliographic reference 55 

descriptive 33 

egg, descriptive 33 

nymphal stages, descriptive 33 

snowi, an injurious cactus insect 34, 41 

Nausigaster unimaeulata, scavenger in cactus 48 

Neoponera villosa incidentally associated with cactus 52 

Nerius flavifrons, scavenger in cactus 49 

Nodonota tristis frequenting flowers of cactus 49 

Noserus emarginatus incidentally associated with cactus 51 

Notogramma stigma incidentally associated with cactus 53 

Nysius angustatus =Nysius ericse. 51 

incidentally associated with cactus 51 

Odontomachus clarus (?) incidentally associated with cactus 52 

Odynerus clusinus incidentally associated with cactus 53 

Oligota sp. , scavenger in cactus 47 

Omalium cacti, scavenger in cactus 47 

Oncerometopus nigriclavus in list of injurious cactus inserts 40 

Onychobaris mystica in list of injurious cactus insects 44 

Opuntia (see also Cactus). 

insects injurious thereto, in order of importance 13 

Opuntia arborescens, Camponotus maculatus vicinus var. nitidvtfentris thereon. . . 53 

flowers frequented by Diadasia australis 50 

rinconis 50 

Lithurgus apicalis opuntise 50 

food plant of Diaspis cacti 42 

echinocacti cacti 42 

opvntix 42 

Disonycha varicorn is 22 

Largus succinctus 40 

Myrmecocystus melliger taken thereon . . .? 53 

probable food plant of Melitarafemaldiaiis 29 

arbuscula, food plant of Chelinidea sp 20 

banburjana, food plant of Cecidomyia opuntise 45 

bernardina, bibliographic reference 54 

food plant of Camopceus palmer i 43 

cycloides, food plant of Pseudococcus sp 42 

elongata, food plant of Diaspis echinocacti opuntim 42 

engelmanni, bibliographic references 54. 55, 56 

flowers frequented by Diadasia australis rinconis 50 

Megachile sidalcese 50 

food plant of aphis 53 

Copestylum marginatum 47 

Diaspis cadi 42 

echinocacti cacti 42 

Gerstxckeria m foilis 43 

1 [y porhagus texanus found t herein 48 

probable food plant of Melitarafemaldiaiis 29 



INDEX. 69 

Page. 

Opuntia ficus-indica, food plant of Diaspis echinocacti 42 

result of work of insect therein described as abnormal 

fruit 35 

fulgida, bibliographic reference 56 

food plant of aphis 52. 53 

Chelinidia ap 20. 40 

Dactylopius tomentosus 42 

Diaspis cacti 42 

echinocacti cacti 42 

Liotropis contaminatus 36, 40 

Onychobaris mystica 44 

Volucella avida a scavenger therein 48 

leptocaulis, bibliographic reference 56 

flowers frequented by Diadasia australis rinconis 50 

food plant of Diaspis echinocacti cacti 12 

Disonycha varicornis 22. 43 

Gerstseckeria rlathrata 30. 44 

Onychobaris mystica 44 

lindheimeri, Apanteles (Pseudapanteles I sp. taken thereat 40 

Euglossa surinamensis thereon 53 

flowers frequented by Diadasia australis rinconis 50 

food plant of Diadasia echinocacti cacti 42 

littoralis, bibliographic reference 56 

flowers frequented by Diadasia australis opuntiic 50 

"longicorns," common name for species of Moneilema 13 

missouricnsis, food plant of Melitara dentata 28 

polyantha, food plant of Dactylopius (Coccus) sp 42 

Melitara prodcn ialis 28 

spp., bibliographic reference 55 

versicolor, food plant of aphis 52. 53 

Chelinidea sp 20 

vulgaris, food plant of Gerstseckeria hubbardi 30. 43 

Melitara prodenialis 28 

Opuntiaspis philococcus. (See Lepidosaphes [O punt it is pis] philococcus. 

Oscinis coxendix incidentally associated with cactus 53 

Othnius senecionis incidentally associated with cactus 52 

Ozam ia lucidalis, an injurious cactus insect 13, 36. 44 

Pachi/condyla harpax incidentally associated with cactus 52 

Paratiphia sp. incidentally associated with cactus 53 

Paromalus consors, scavenger in cactus 48 

gilensis, scavenger in cactus 48 

opuntiir, scavenger in cactus 48 

sp., scavenger in cactus 48 

Pasimachus californicus incidentally associated with cactus 51 

depressus incidentally associated with cactus 51 

Pelosoma capillosum, scavenger in cactus 47 

Perdita megacephala frequenting flowers of cactus ' 50 

I'crisporium sp., fungous disease of cactus, probable dissemination by Chelinidea 

vittigera 17 

Pheidole sp. incidentally associated with cactus 52 

Phileurus cribrosus incidentally associated with cactus 51 

Phorbia fusdeeps, scavenger in cactus 49 

Phoroccra comstocki, parasite of cactus insect i Melitara I 46 

Melitara junctolineella 27 



70 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 

Page. 

Phyllotreta piisilla frequenting flowers of cactus 49 

Physetoporas grossulus, scavenger in cactus 47 

PJatymetopius fuscifrons in list of injurious cactus insects 41 

I'hitynota rostrana, an injurious cactus insect 13. 36, 45 

Platypedia putnami in list of injurious cactus insects 41 

Polistes, three species injurious to cactus 13 

Polistes flavus, an injurious cactus insect 36, 45 

rubiginosus, an injurious cactus insect 36, 45 

texanus, an injurious cactus insect 36, 45 

Pontia protodice incidentally associated with cactus 52 

I'ii iiolepis viridula subsp. melanderi incidentally associated with cactus 53 

Prickly pear. (See Cactus and Opuntia.) 
Pristocelis texanus. (See Trichochrous texanus.) 

Pmarno valvata in list of injurious cactus insects 41 

Pseudococcus longispinus in list of injurious cactus insects 42 

obscurus, bibliographic reference 57 

in list of injurious cactus insects 42 

sp. in list of injurious cactus insects 42 

virgatus in list of injurious cactus insects 42 

Pseudomyrma brunnca incidentally associated with cactus 52 

Pscudoparlatoria parlatorioidcs in list of injurious cactus insects 42 

Pseudoscorpionuke taken from pulp of Cercus giganteus 53 

Pycnomutilla texana incidentally associated with cactus 53 

Randia, food plant of Platynota rostrana 45 

Rehnia spinosa incidentally associated with cactus 51 

Rhagodera n. sp. incidentally associated with cactus 51 

Jx'ipersia sp. in list of injurious cactus insects 42 

/,'it( Ilia sp., scavenger in cactus 49 

Rivinia, food plant of Platynota rostrana 45 

Saluria ardiferella, enemy of cactus insect (Dactylopins confusus i 24, 46 

Saprinus pennsylvanieus, scavenger in cactus 48 

Sapromyza vulgaris, scavenger in cactus 49 

Scale insects. (See Coccidae.) 

Scatopse sp., scavenger in cactus 48 

Scymnus hornii, enemy of cactus insect (Dactylopius confusus) 24, 46 

loeivii, enemy of cactus insect (Dactylopius confusus) 24, 46 

Sinea raptoria, enemy of cactus insects 45 

Sixeonotus hdciceps, an injurious cactus insect 36, 41 

-^ in icrips hypocoproides, scavenger in cactus 48 

Smicronyx spretus incidentally associated with cactus 52 

Si ilanacese, Lineodcs Integra reared thereon 52 

S; iwbugs, injury to Mammillaria phellosperma 53 

Split nophorus spinolx. (See Cactophugus spinolx.) 

s jinngophora apicidentata incidentally associated with cactus 50 

liniuiieipennis incidentally associated with cactus 50 

Stictomyia lougicornis, an injurious cactus insect 39 

scavenger in cactus 49 

Stipator grandis incidentally associated with cactus 51 

haldemanni incidentally associated with cactus 51 

mitchelli incidentally associated with cactus 51 

nigromarginata incidentally associated with cactus 51 

pratti incidentally associated with cactus 51 

Simnalocera rubra incidentally associated with cactus 52 



INDEX. 71 

Page. 

Slylopidea picta, an injurious cactus insect 13, 22-23, 41 

Tachinoderus grandis, scavenger in cactus 47 

Tempyra bigutlula incidentally associated with cactus 51 

Terapus mniszechi, a myrmecophile 48 

scavenger in cactus 4S 

Termes flavipes, an injurious cactus insect 25, 40 

Tetranychus opuntise, bibliographic reference 57 

in list of cactus insects 40 

Thyridopteryx ephemerxformis, prey of Dicymolom ia julianqlis .» 44 

Tobacco extract in control of cottony cochineal insect 25 

Trichochrous (Pristocelis) texanus injuring blooms of cactus 32, 12 

Trichodes bibalteatus, enemy of Melitara and other cactus insects 46 

Trichopteryx sp., scavenger in cactus 47 

Triorophus nodiceps incidentally associated with cactus 51 

Tuna as food for man 10 

Tyrus elongatus, scavenger in cactus 47 

Ulosonia vnarginata incidentally associated with cartas 52 

Volucella avida, an injurious cactus insect 3s 

scavenger in cactus 48 

esuriens, an injurious cactus insect 38 

scavenger in cactus 48 

fasciata, an injurious cactus insect 38 

bibliographic references 54 

scavenger in cactus 48 

pusilla, an injurious cactus insect 38 

scavenger in cactus 48 

Whale-oil soap in control of cottony cochineal insect 25 

Xantholinus dmiidiatus, scavenger in cactus 47 

Xanthopygus cacti, scavenger in cactus 47 

Yuccas, food plants of Sixeonotus luteiceps 36, 41 

Zophodia dilatifasciella, enemy of cactus insect (Dactylopius confusus) 24, 46 

o 



62d Congress [ 
2d Session \ 



SENATE 



| Document 
l No. 305 



MEXICAN COTTON-BOLL WEEVIL 



MESSAGE FROM THE 
PRESIDENT OF THE UNITED STATES 

TRANSMITTING 

A COMMUNICATION FROM THE 
SECRETARY OF AGRICULTURE 
SUBMITTING A REPORT ON THE 
MEXICAN COTTON -BOLL WEEVIL 










WASHINGTON 

1912 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate I. 




Cotton Plant Attacked by Boll Weevil. 

a, Hanging dry square infested by weevil larva; b, flared square, with weevil punctures: 
c, cotton boll, sectioned, showing attacking weevil and weevil larva in its cell. 

(Original.) 



62d Congress ) SENATE - Document 

2d Session ) ( No. 305 



MEXICAN COTTON-BOLL WEEVIL 



MESSAGE FROM THE 
PRESIDENT OF THE UNITED STATES 

TRANSMITTING 

A COMMUNICATION FROM THE 
SECRETARY OF AGRICULTURE 
SUBMITTING A REPORT ON THE 
MEXICAN COTTON -BOLL WEEVIL 



\fT\i 

4^ 



WASHINGTON 

1912 



LETTER OF TRANSMITTAL. 



To the Senate and House of Representatives: 

I transmit herewith for the information of the Congress a commu- 
nication from the Secretary of Agriculture, accompanying the manu- 
script of a report on the Mexican Cotton-boll Weevil: A Summary of 
the Results of the Investigation of this Insect up to December 31, 
1911. (Bulletin No. 114, Bureau of Entomology.) 

The report contains valuable information of great public interest 
to cotton planters of this country and those depending upon the 
cotton-plant industry, and I cordially indorse the recommendation 
of the Secretary that the report be printed for distribution by Congress 
as well as by the department. 

Wm. H. Taft. 

The White House, February 12, 1912. 

3 



LETTERS OF SUBMITTAL 



Department of Agriculture, 

Office of the Secretary, 

Washington, February 8, 1912. 
To the President of the United States. 

Mr. President: I have the honor to submit herewith, for your 
information and that of the Congress of the United States, a bulletin 
entitled "The Mexican Cotton-boll Weevil: A Summary of the 
Results of the Investigation of tins Insect up to December 31, 1911," 
by Messrs. W. D. Hunter and W. D. Pierce of this department. 
This is an elaboration of a bulletin published in 1905 and of which a 
special edition was ordered by Congress. Since that date the weevil 
has spread throughout the State of Louisiana and has entered the 
States of Arkansas, Mississippi, and Alabama, and threatens to spread 
throughout the entire cotton-growing area east of the arid regions. 
In the course of tins eastward and northward spread, new conditions 
have been encountered; the habits and life history of the weevil have 
undergone some change, and it has met with new parasites and 
natural enemies. There is a great demand among the cotton planters 
of this country and among those dependent upon the cotton-planting 
industry for the information contained in this bulletin, and, in view 
of this fact, I respectfully recommend that this report be transmitted 
to Congress, together with the maps, illustrations and diagrams 
accompanying it, to be printed by order of Congress; and I further 
recommend that not less than 10,000 copies be printed for the use 
of this department, in addition to such number as Congress may 
order for the use of its Members. 

I have the honor to remain, Mr. President, 
Very respectfully, 

James Wilson, Secretary. 

Department of Agriculture. 

Bureau of Entomology, 
Washington, D. C, January, 1912. 
Sir: I have the honor to transmit herewith and to recommend 
for publication a manuscript entitled "The Mexican Cotton-boll 
Weevil: A Summary of the Results of the Investigation of this 
Insect up to December 31, 1911," prepared by Messrs. W. D. Hun- 
ter and W. D. Pierce, of tins bureau. 

This manuscript contains in the briefest possible space an account 
of the exhaustive investigations of the Mexican cotton-boll weevil 
which have been conducted by this bureau for some years past. The 
last comprehensive bulletin on this subject was issued in 1905 and 
is now far out of date. There is urgent demand for information on 
this important pest, and this demand will undoubtedly continue as 
the insect invades new regions. 

Respectfully, L. 0. Howard, 

Entomologist and Chief of Bureau. 
Hon. James Wilson, 

Secretary of Agriculture. 

5 



PREFACE. 



Early in 1905 the Bureau of Entomology published as Bulletin 51 
an account of the information concerning the Mexican cotton-boll 
weevil which was available at that time. Since 1905 the work on 
the investigation of this important insect has been continued by the 
Bureau of Entomology and by various other agencies. As the result 
of this recent work certain features of the life history of the pest have 
received full treatment in publications of the bureau. This is the 
case with hibernation, 1 natural control, 2 parasites, 3 proliferation, 4 and 
repression. 5 Important contributions have been made by State 
agencies. The result has been that the original bulletin has been 
out of date for some time. On many topics the amount of informa- 
tion now available is more than double that at hand at the time the 
previous publication was issued. Moreover, it seems advisable that 
the history of the pest in the United States and an account of the 
losses occasioned by it should be brought up to date. For these 
reasons the present publication has been prepared to include all of 
the more important available information concerning the boll weevil. 
It is based upon Bulletin 51, from which many extracts have been 
used, and will supersede that publication. 

In the nature of the case it is impossible to include all of the data 
which have been published with reference to certain phases of the 
life history of the boll weevil, such as hibernation and parasite con- 
trol. In all such cases, however, the main essentials regarding these 
special topics have been incorporated. Persons who desire more 
detailed information may consult the various special publications, 
which are still available. 

As might be supposed the accumulation of many additional data 
has necessarily changed some of the conclusions drawn in the earlier 
publication. It is to be noted, however, that these changes are 
generally of little consequence. 

The investigation of the boll weevil was begun by the then Division 
of Entomology in 1895 and has been continued, more or less con- 
stantly, to the present date. The vast amount of information which 
has thus been accumulated is to be credited to a large number of 
entomologists, many of whom are now doing work in other fields, 
The earlier investigations of the weevil were conducted by Dr. L. O. 
Howard and Messrs. C. L. Marlatt, C. H. T. Townsend, E. A. Schwarz. 
and Frederick Mally. The State officers who have assisted mate- 
rially in this work have been the entomologists of Texas, Messrs. 
E. D. Sanderson, A. F. Conradi, C. E. Sanborn, and Wilmon Newell; 
of Louisiana, Messrs. H. A. Morgan, Wilmon Newell, J. B. Garrett, 

> Bull. 77, Bur. Ent., U. S. Dept. Agr., 1909. < Bull. 59. Bur. Ent., U. S. Dept. Agr.. 1906. 

' Bull. 74, Bur. Ent., U. S. Dept. Agr., 1907. & Farmers' Bull. 344, U. S. Dept. Agr., 1909. 

3 Bull. 100, Bur. Ent., U. S. Dept. Agr., 1912. 



8 PREFACE. 

T. C. Barber, H. Dean, M. S. Dougherty, A. H. Rosenfeld, and G. A. 
Runner; of Oklahoma, Messrs. C. E. Sanborn and A. L. Lovett; of 
Arkansas, Dr. George F. Adams; of Mississippi, Messrs. Glenn W. 
Herrick, R. W. Harned, S. F. Blumenfeld, and R. N. Lobdell; and of 
Alabama, Dr. W. E. Hinds and Messrs. W. F. Turner and I. W. Car- 
penter. The work has been facilitated by the commissioners of 
agriculture of the various States, including Col. Charles Shuler, for- 
mer commissioner of agriculture of Louisiana, Mr. H. E. Blakeslee, 
commissioner of agriculture of Mississippi, and Mr. F. W. Gist, former 
commissioner of agriculture of Oklahoma. 

The agents of the Bureau of Entomology who have contributed to 
tins bulletin are: Messrs. F. C. Bishopp, J. C. Crawford, R. A. Cush- 
man, F. L. Elliott, A. F. Felt, C. W. Flynn, J. B. Garrett, W. H. 
Gilson, S. Goes, G. H. Harris, W. E. Hinds, W. H. Hoffman, T. E. 
Holloway, C. E. Hood, W. A. Hooker, R. C. Howell, C. R. Jones, B. T. 
Jordan, O. M. Lander, Thomas Lucas, E. A. McGregor, J. D. Mitchell, 
A. C. Morgan, A. W. Morrill, D. C. Parman, T. C. Paulsen, H. Pinkus, 
F. C. Pratt, V. I. Safro, E. A. Schwarz, J. S. Slack, G. D. Smith, 
H. S. Smith, C. S. Spooner, E. S. Tucker, G. N. Wolcott, and W. W. 
Yothers. Of these agents Dr. W. E. Hinds, who for several years 
was the principal assistant in the cotton boll weevil investigations 
of this bureau, was the most extensive contributor. To him we owe 
a large share of the accurate data on the life history and habits of 
the boll weevil. He also did a large amount of work in the prepara- 
tion of Bulletin 51, upon which this publication is based. We have 
attempted throughout the bulletin to credit the various agents with 
the work for which they have been directly responsible, but in tins 
place it must be stated that the results obtained are due to the 
faithful and efficient service of the whole corps of entomologists who 
have been associated with the writers. The work has also been 
greatly facilitated by the constant interest and encouragement of 
the chief of the bureau. 

Special credit is due to Mr. E. S. Tucker for skillful preparation of 
the plates. 

The Authors. 



CONTENTS. 



Page. 

Origin and history 15 

Distribution 20 

Losses due to the boll weevil 21 

Indirect losses caused by the boll weevil 26 

Compensation for losses caused by the 1 toll weevil 26 

Prospects 27 

Insects often mistaken for the boll weevil 29 

Food plants of the boll weevil 31 

Life history 32 

Summary 32 

Description 33 

The ee;s; 33 

The larva 33 

The pupa 34 

The adult 34 

Before emergence 34 

Description of adult 35 

Size of weevils 35 

Weight of weevils 35 

Color of weevils 35 

Secondary sexual characters 37 

Seasonal history 38 

The adult weevil 38 

Emergence 38 

Changes after emergence 38 

Protective habits 38 

Food habits 38 

Ability to locate cotton 41 

Feeding habits of hibernated weevils 41 

Destructive power by feeding 42 

Attractiveness of various substances 42 

Sense of color 43 

Movements on food plant 43 

Effects upon squares and bolls of feeding by the boll weevil 44 

Susceptibility of various cottons 45 

Duration of life of adult weevils 47 

Cannibalism 50 

Seasonal proportion of sexes 51 

Fertilization 52 

Age at 1 leginning of copulation 52 

Sexual attraction and duration of copulation 52 

Duration of fertility 52 

Parthenogenesis 53 

Oviposition 53 

Age at 1 leginning of oviposition 53 

Examination of squares before oviposition 54 

Selection of uninfested squares for oviposition 54 

Dependence of reproduction upon food obtained from squares 55 

Place of egg deposition 56 

The act of oviposition 56 

Time required to deposit an egg 58 

Stimulating effect of abundance of squares upon egg deposition. . 58 

Activity of weevils in different parts of the day 58 

Seasonal rate of oviposition 59 

Is the fecundity of the weevil decreasing? 60 

Period of oviposition 61 

Effects of oviposition upon squares 61 

Probable original breeding habit 62 

9 



10 CONTENTS. 

Seasonal history — Continued. Page. 

The egg ." 62 

Duration of egg stage G2 

Hatching 64 

Hatching of eggs laid outside of cotton fruit 64 

Eating of eggs deposited outside 64 

Percentage of eggs that hatch 65 

The larva 65 

Food habits 65 

Growth 65 

Molts 66 

Duration of larval stage 6o 

Pupal cells 67 

Pupation 67 

The pupa 67 

Activity 67 

Duration of pupal stage 67 

Percentage of weevils developed from infested squares 68 

Life cycle 69 

Duration of life cycle 69 

Sexual variations 69 

Variations due to location of developing stage 69 

Variations due to time of falling of infested squares 69 

Variations due to temperature 70 

Variations of development in bolls 72 

Miscellaneous variations 72 

Development of weevils in the squares which never fall 73 

Development during winter 73 

Seasonal abundance 74 

Broods or generations 74 

Possible annual progeny of one pair of hibernated weevils 76 

Progress of infestation in fields 77 

Effect of maximum infestation upon weevil multiplication 79 

Status examinations 80 

Relation of weevils to top crop 81 

Variations in abundance of the weevil from year to year 83 

Natural dissemination 85 

Spring search for cotton 85 

Spring spread within the field '. 86 

Summer flights 86 

Fall dispersion 87 

Hibernation flight 90 

Other forms of natural spread 90 

Artificial dissemination 91 

Movement of seed cotton 91 

Movement of cotton seed 91 

Baled cotton 93 

Passing vehicles 93 

Movement of farm hands 93 

Unexplained sporadic occurrences 94 

Intentional transportation of the weevil 94 

Hibernation 94 

Methods of study of hibernation 95 

Entrance into hibernation 96 

Sources of weevils entering hibernation 96 

Stages entering hibernation 96 

Time of entering hibernation 97 

Number of adult weevils entering hibernation 98 

Shelter during hibernation 100 

Activity during the hibernation period 103 

Duration of hibernation period 103 

Average length of hibernation period 103 

Relation of shelter to duration of hibernation 105 

Emergence from hibernation 107 

Time of emergence 107 

Rate of emergence 108 

Survival of hibernated weevils 110 

Relation of fall destruction to survival Ill 



CONTENTS. 11 

Hibernation — Continued. Page. 
Survival of hibernated weevils — Continued. 

Relation of shelter to survival 112 

Relation of climate to survival 112 

Longevity of hibernated weevils 114 

Maximum length of life 115 

Relation of emergence and longevity to time of planting 116 

Nature of weevil activity following emergence from hibernation 116 

Natural control 118 

Climatic control 120 

Climatic influences on vitality and activities 121 

Field observations on mortality due to heat and dryness 122 

General discussion of the relations of temperature to the boll weevil. . 125 

Upper zone of fatal temperature 126 

Zone of aestivation 127 

Zone of activity 127 

Zone of hibernation 127 

Lower zone of fatal temperatures 128 

Fatal variations of temperature 129 

Effects of flooding upon the weevil 131 

Plant control 132 

Proliferation 132 

Other phases of plant control 135 

Diseases 136 

Parasitic and predatory insect enemies 136 

A brief summary of the insect species attacking the boll weevil 136 

Birds 145 

Repression 147 

Effect of burial of squares and weevils 147 

Laboratory experiments in burial 148 

Burial of adult weevils at time of hibernation 148 

Conclusions from burial experiments 148 

Insecticides 149 

Powdered arsenate of lead 150 

Machines 151 

Field machinery 151 

Ginning machinery 152 

Futile methods which have been suggested 153 

Mineral paint and cottonseed oil 153 

Spraying 153 

Sulphur 153 

Paris green 154 

Trapping at light 154 

Other proposed remedies 154 

Requirements of a satisfactory method of boll-weevil control 155 

Basis for means of repression 155 

Summary of means of repression of the boll weevil 160 

Destroying the boll weevil in cotton seed 162 

Legal restrictions regarding the boll weevil 164 

United States Statute 164 

Quarantines of the several States 164 

Bibliography 169 

Index 176 



ILLUSTRATIONS, 



PLATES. 

Page. 
Plate I. Cotton plant attacked by boll weevil, a, Hanging dry square 
infested by weevil larva; b, flared square with weevil punctures; 
c, cotton boll, sectioned, showing attacking weevil and weevil 

larva in its cell Frontispiece. 

II. The boll weevil and insects often mistaken for it. a, The cotton 
boll weevil, Anthonomus grandis; b, the mallow weevil, Anthono- 
ruusfulvus; c, the southern pine weevil, Pissodes nemorensis; d, the 
cottonwood flower weevil, Dorytomus mucidus; e, Conotrachelus 
erinaceus; /, the pecan gall weevil, Conotrachelus elegans 28 

III. Anatomical structure of the boll weevil, a, Dorsal view of anal 

segments of larva; b, front view of head and anterior segments 
of larva; c, ventral view of anal segments of larva; d, lateral view 
of adult; e, lateral view of larva;/, ventral view of adult; g, dorsal 
view of adult with wings spread; h, ventral view of pupa; i, ventral 
view of anal segments of pupa; j, ventral view of anterior portion 
of pupa 32 

IV. The adult boll weevil and emergence holes, a, Squares of Peruvian 

cotton showing emergence holes of the Peruvian cotton square 
weevil; b, square of upland cotton showing emergence hole of the 
cotton boll weevil; c, adult boll weevil on cotton square; d, adult 
boll weevil puncturing cotton square; e, adult boll weevil emerg- 
ing from cotton boll;/, small dry bolls showing emergence holes; g, 

hull of boll with weevils found hibernating 36 

V. Effects of boll weevil attack on leaf and squares, a, Cotton leaf much 
fed upon by adults; b, square with two egg punctures; c, flared 
square with many feeding punctures; d, square prevented from 
blooming by puncture; e, bloom injured by feeding punctures;/, 
poor blooms caused by feeding punctures 40 

VI. Injury by boll weevil to squares, a, Bloom checked by attacks of 
larva; b, square opened, showing grown larva; c, square opened, 
showing pupa; d. dwarfed boll opened, showing one larva and two 
pupae; e, weevil escaping from square;/, emergence hole of adult 

in square 44 

VII. Injury by boll weevil to bolls, a, Three larvae in boll; b, emergence 
hole in dry, unopened boll; c, two larvae in boll; d, weevils punctur- 
ing boll; e, opened boll with two locks injured by weevil;/, large 

bolls severely punctured 44 

VIII. Field conditions in territory occupied by the boll weevil. Fig. a. — 
Newly planted cotton field, with sprouts from overwintered cotton 
roots. Fig. b. — Fallen infested squares 76 

IX. Relation of boll weevil cells to seed, a, Boll weevil pupa found in 
cotton seed; b, boll weevil pupa in cell of lint from boll; c, weevil 
cell in dwarfed cotton boll containing live pupa taken among seed; 

d, weevil cells in bolls; e, cotton seeds 92 

X. Fig. a. — Boll weevil remains after passing through fan from gin. 

Fig. b. — Ten-sectioned hibernation cage 96 

XI. Hibernation conditions for the boll weevil. Fig. a. — Cotton field 
adjacent to timber covered with Spanish moss. Fig. b. — Proxim- 
ity of moss-laden trees, conducing to high infestation by weevil. . 96 
XII. Hibernation conditions for the boll weevil. Fig. a. — Standing dead 
timber and forest environment favorable for hibernation of weevils. 

Fig. b. — Litter in forest , suitable for hibernation of weevils 100 

XIII. Hibernation conditions for the boll weevil. Fig. a.— Spanish moss 
on trees, very favorable for hibernation of weevils. Fig. b. — 
Density of Spanish moss as a protection to weevils in hibernation. . 100 
12 



ILLUSTBATIONS. 13 

Page. 
Plate XTV. Natural control of the boll weevil, a, Pilose and nonpilose stems 
of cotton; b, larva of boll weevil crushed by proliferation; c, 
pupaof Catolaccus incertus on pupa of cotton-boll weevil; tf, larva 
of Microbracon mellitor attacking boll weevil larva; c, /, holes 
gnawed by Solenopsis geminata in effecting entrance into in- 
fested squares 120 

XV. The difference between hanging and fallen squares. Fig. a. — 
Cotton squares with short absciss layer, permitting infested 
squares to fall. Fig. b. — Cotton squares with long absciss layer, 
retaining infested forms to hang and dry 136 

XVI. Boll weevil ants, a, Eciton commutatus; b, Cremastogaster lineo- 
luta; c, Dorymyrmex pyramicus; d, Monomorium pharaonis; c, 

Solenopsis molesta; f, Iridomyrmex analis 140 

XVII. Boll weevil parasites, a, Eurytoma tylodermatis, male; b, Eury- 
toma tylodermatis, female; c, MicrodontOTnerusanihonomi, female; 
cf, antenna of same; d, JSabrocytus pierced, female; d' '. antenna 
of same; e, Catolaccus hunteri, female; c' , antenna of same; /', 

antenna of Catolaccus incertus 140 

XVIII. Boll weevil parasites, a, Lariophagus texanus, female; b, emer- 
gence hole of Tetrastichvs hunteri from weevil larva; c, Tetra- 
stichus hunteri, female; & ', antenna of same; d, puparium of 
Ennyomma globosa in weevil larva; c, Ennyomma globosa; f, 
( 'erambycobius cyaniceps, female;/', natural position of same.. 144 

XIX. Effect of Paris green on cotton. Fig. a. — Cotton before treat- 
ment with Paris green. Fig. b. — Cotton one week after treat- 
ment with Paris green 148 

XX. Cultural control of the boll weevil. Fig. a. — Early fall destruc- 
tion of stalks, the fundamental method for controlling the boll 
weevil. Windrowing stalks for burning. Fig. b. — Chain cul- 
tivator passing through cotton rows 152 

XXI. Use of chain cultivator. Fig. a. — Space between cotton rows 
before passage of cultivator. Fig. b. — Effect after passage of 

cultivator 152 

XXII. Results of early and late planting of cotton. Fig. a. — Late- 
planted cotton under boll-weevil conditions, given same cul- 
ture as early planting. Fig. b. — Early-planted cotton adjoining 
the late planting under same conditions 160 

TEXT FIGURES. 

1. Map showing the distribution of the cotton-boll weevil on January 1, 1912. 20 

2. Map of portion of Texas, showing movement of the center of cotton produc- 

tion west ward 25 

3. Secondary sexual characters of Anthonomus grandis 37 

4. Cotton-boll weevil: Head showing rostrum, with antennae near middle and 

mandibles at end; mandible 39 

5. Diagram showing average activity of five female boll weevils 59 

6. Diagram to illustrate influence of temperature on average rate of oviposition 

of boll weevil 60 

7. Diagram illustrating relationship of temperature to the egg period of the boll 

weevil at Victoria, Tex., in 1902 63 

8. Diagram illustrating relationship of temperature to the egg period of the boll 

weevil and showing variations due to humidity 64 

9. Diagram illustrating relationship of temperature to larval period of the boll 

weevil and showing range due to humidity 66 

10. Diagram illustrating relationship between temperature and the pupal 

period of the boll weevil and showing variations due to humidity 67 

11. Diagram illustrating effect of time of falling of infested squares upon period 

of development of boll weevil at Victoria, Tex., August, 1904 70 

12. Diagram illustrating temperature control of developmental period of the 

boll weevil 71 

13. Diagram illustrating normal developmental period of boll weevil in squares, 

by months, at Victoria, Tex., Ardmore, Okla., and Vicksburg, Miss 71 

14. Diagram illustrating seasonal history of the boll weevil at Victoria, Tex. . . 75 

15. Status of the boll weevil in Texas in August, 1906; percentage of infestation 

of all forms 79 



14 ILLUSTRATIONS. 

Page. 

16. Status of the boll weevil in Texas in August, 1908; percentage of infestation 

of all forms 80 

17. Status of the boll weevil in Texas in August, 1909; percentage of infestation 

of all forms 81 

18. Status of the boll weevil in Texas in August, 1910; percentage of infestation 

of all forms 82 

19. Status of the boll weevil in Texas in August, 1911; percentage of infestation 

of all forms 83 

20. Curves of numerical strength of the boll weevil and its parasites 84 

21. The spread of the cotton-boll weevil from 1892 to 1911 88 

2'2. Diagram illustrating average length of hibernation period of the boll weevil 

as related to date of entering hibernation 1 06 

23. Diagram illustrating relations of effective temperature and precipitation to 

date of beginning emergence of the boll weevil 107 

24. Diagram illustrating average rate of emergence of the boll weevil from hiber- 

nation in Texas and Louisiana 109 

25. Diagram illustrating average longevity of boll weevils after emerging on a 

given date 115 

26. Diagram to illustrate the zones of temperature in their relations to the 

activities of the boll weevil 126 

27. Map showing dates of first killing frost in the area infested by the boll 

weevil, in the winter of 1909-10 129 

28. Map showing normal dates of first killing frost in the southern United States. 129 

29. Map showing minimum temperatures on October 29 and 30, 1910, the date 

of the first killing frost in Louisiana 130 

30. Map showing minimum temperatures in the winter of 1910-11 in Louisiana. 130 

31. Evarthrus sodalis an enemy of the boll weevil 138 

32. Chauliognathus marginatus an enemy of the boll weevil 1 38 

33. Hydnocera pubescens an enemy of the boll weevil 139 

34. Apparatus for fumigating cotton seed in the sack 163 



THE MEXICAN COTTON-BOLL WEEVIL: A SUM- 
MARY OF THE INVESTIGATION OF THIS INSECT 
UP TO DECEMBER 31, 1911. 



ORIGIN AND HISTORY. 

There is very little certainty regarding the history of the Mexican 
cotton-boll weevil before its presence in Texas came to the attention 
of the Division of Entomology in 1894. The species was described 
by Boheman in 1843 from specimens received from Vera Cruz, and 
was recorded by Suffrian in 1871 as occurring at Cardenas and San 
Cristobal, in Cuba. Written documents in the archives at Mon- 
clova, in the State of Coahuila, Mexico, indicate that the cultivation 
of cotton was practically abandoned in the vicinity of that town 
about the year 1848, or at least that some insect caused very great 
fears that it would be necessary to abandon the cultivation of cotton. 
A rather careful investigation of the records makes it by no means 
clear that the insect was the boll weevil, although there is a rather 
firmly embedded popular opinion in Mexico, as well as in the southern 
United States, that the damage must have been perpetrated by that 
species. So far as the accounts indicate, it might have been the 
bollworm (Helioihis obsoleta Fab.) or the cotton caterpillar (Alabama 
argillacea Hiibn. ). 

From the time of the note by Suffrian regarding the occurrence of 
the weevil in Cuba in 1871, up to 1885, there has been found no pub- 
lished record concerning it. In 1885, however, Dr. C. V. Riley, then 
Entomologist of the Department of Agriculture, published in the 
report of the Commissioner of Agriculture a very brief note to the 
effect that Anthonomus grandis had been reared in the department 
from dwarfed cotton bolls sent by the late Dr. Edward Palmer from 
northern Mexico. 1 This is the first account in which the species is 
associated with damage to cotton. The material referred to was 
collected in the State of Coahuila, presumably not far from the town 
of Monclova. 

i The following is a copy of the original letter by Dr. Palmer: 

Eagle Pass, Tex., Sept. 28. 1880. 
The Commissioner of Agriculture. 

Sir: Previous to leaving Monclova, Mexico, for this place I visited some fields planted with cotton. 
Seeing but few bolls of cotton, examination revealed the cause. An insect deposits its egg and the boll 
falls; thus some plants had only two or three, others five or six bolls, while underneath the loaves, in the 
shade thereof, were many that had fallen there in the moist shade to lay for the larva to hatch. Please 
find inclosed insects and many of the injured bolls, some newly punctured, others taken from under the 
plant. 

Monclova, Mexico, and the surrounding country a few years ago was famous for its large supply of cotton; 
at this time none can be grown, owing to the destructive insect, samples of which are sent. The inhabit- 
ants would be glad to hear of a remedy, upon which matter in the future I will communicate with your 
department. 

Your obedient servant, Edward Palmer. 

The specimens were sent by Dr. L. O. Howard to Mr. Henry Dike, who transmitted them to Dr. George 
Horn, of Philadelphia. In turn Dr. Horn forwarded the material to Dr. Sall6, in Paris, who made the 
determination. 

15 



16 THE MEXICAN COTTON-BOLL WEEVIL. 

After the American occupation of Cuba the boll weevil began to 
attract considerable attention in that island. In 1902 it was ob- 
served that the weevil was quite injurious to cotton at Cayamas, 
Cuba. This place was visitecl by Mr. E. A. Schwarz, of the Bureau 
of Entomology, in the spring of 1903. He found that the native food 
plants of the weevil in Cuba were the "wild" or " loose" cotton 
(Gossypium brasiliense) and the native "kidney" cotton — both tree 
cottons. 

The spread of the boll weevil in Mexico appears to have begun 
prior to 1892. In that year it appeared at Sabinas, State of Coahuila, 
and about this time or earlier it appeared at San Juan Allende, 
Morelos, Zaragoza, and Matamoras, Mexico. It crossed the Rio 
Grande at Brownsville probably before 1892. At any rate, during 
that year it caused considerable loss at Brownsville. In 1894 it had 
spread to half a dozen counties in the Brownsville region, and during 
the last months of the year was brought to the attention of the 
Division of Entomology as an important enemy of cotton. Mr. 
C. H. T. Townsend was immediately sent to the territory affected. 
His report, published in March, 1895, dealt with the life history and 
habits of the insect, which were previously entirely unknown, the 
probable method of its importation, and the damage that might 
result from its work, and closed with recommendations for fighting 
it and preventing its further advance in the cotton-producing regions 
of Texas. It is much to be regretted that at that time the State 
of Texas did not adopt the suggestion made by the Bureau of Ento- 
mology that a belt be established along the Rio Grande in wliich 
the cultivation of cotton should be prohibited, and thus the advance 
of the insect be cut off. 1 The events of the last few years have 
verified the predictions of the Division of Entomology in view of 
the advance made and the damage caused by the insect. 

In 1895 the insect was found by the entomologists of the Division 
of Entomology, who continued the investigation started the year 
before, as far north as San Antonio and as far east as Wharton. 
Such a serious advance toward the cotton-producing region of the 
State caused the Bureau of Entomology to continue its investiga- 
tions during practically the whole season. The results of this work 
were incorporated in a circular by Dr. L. O. Howard, published early 
in 1896, in both Spanish and English editions. 

An unusual drought in the summer of 1896 prevented the maturity 
of the fall broods of the weevil, and consequently there was no 
extension of the territory affected. During 1896 the investigations 
were continued, and the results published in another circular issued 
in February, 1897. This circular was published in Spanish and 
German as well as English editions, for the benefit of the very large 
foreign population in southern Texas. 

The season of 1897 was in many respects almost as unfavorable as 
that of 1896, but the pest increased its range to the region about 
Yoakum and Gonzales. Although this extension was small, it was 
exceedingly important, because the richest cotton lands in the 
United States were beginning to be invaded. The problem had 
thus become so important that Mr. C. H. T. Townsend was stationed 

1 This suggestion was brought to the attention of the General Assembly of Texas by the then Assistant 
Secretary of Agriculture, Dr. C. W. Dabney, who went to Austin for that purpose. 



ORIGIN AXD HISTORY. 17 

in Mexico, in a region supposed to be the original home of the insect, 
for several months to discover, if possible, any parasites or diseases 
that might be affecting it, with the object of introducing them to prey 
upon the pest in Texas. Unfortunately, nothing was found that gave 
any hope of material assistance in the warfare against the weevil. 

The season of 1898 was very favorable for the insect. Investiga- 
tions by the Bureau of Entomology were continued, and a summary 
of the work, dealing especially with experiments conducted by Mr. 
C. L. Marlatt in the spring of 1896, was published in still another 
circular. During this year the first of a long series of conventions 
to discuss the boll weevil was held. This meeting took place at 
Victoria, Tex., on October 12, and was attended by many planters, 
bankers, and merchants. 

At this time the Legislature of the State of Texas made provision 
for the appointment of a State entomologist and provided a limited 
appropriation for an investigation of means of combating the boll 
weevil. In view of this fact the Bureau of Entomology discontinued 
temporarily the work that had been carried on through agents kept 
in the field almost constantly for four years, and all correspondence 
was referred to the State entomologist of Texas. Unfortunately, 
however, the insect continued to spread, and it soon became 
apparent that other States were threatened. This caused the work 
to be taken up anew by the Bureau of Entomology in 1901, in accord- 
ance with a special appropriation by Congress for an investigation 
independent of that which was being carried on by the State of 
Texas, and with special reference to the discovery, if possible, of 
means of preventing the insect from spreading into adjoining States. 

In accordance with the provision mentioned the senior writer was 
sent to Texas in March, 1901, and remained in that State until 
December. He carried on cooperative work upon eight large plan- 
tations in the region infested by the weevil. The result of his obser- 
vations was to suggest the advisability of a considerable enlargement 
of the scope of the work. It had been found that simple cooperative 
work with the planters was exceedingly unsatisfactory. The need 
of a means of testing the recommendations of the Bureau of Ento- 
mology upon a large scale, and thereby furnishing actual demonstra- 
tions to the planters, became apparent. Consequently, in 1902, at 
the suggestion of the Department of Agriculture, provision for the 
enlargement of the work was made by Congress. Agreements were 
made with two large planters in typical situations for testing the 
principal features of the cultural system of controlling the pest 
upon a large scale. At the same time the headquarters and labora- 
tory of the special investigation were established at Victoria. The 
results of the field work for this year were published in the form of 
a Farmers' Bulletin. During this season cooperation was carried 
on with the Mexican commission charged with the investigation of 
the boll weevil in that country, which was arranged on the occasion 
of a personal visit of Dr. L. O. Howard to the City of Mexico in the 
fall of the preceding year. In November an enthusiastic convention 
of planters and merchants to discuss the problems was held at 
Dallas, Tex. 

The favorable reception by the planters of Texas of the experi- 
mental field work conducted during 1902 and the increase in the 

28873°— S. Doc. 305, 62-2 2 



18 THE MEXICAN COTTON-BOLL WEEVIL. 

territory occupied by the pest brought about an enlarged appropria- 
tion for the work of 1903. It thus became possible to increase the 
number and size of the experimental fields as well as to devote more 
attention to the investigation of matters suggested by previous 
work in the laboratory. Seven experimental and demonstrational 
farms, aggregating 558 acres, were accordingly established in as 
many distinct cotton districts in Texas. 

During 1903 the weevil was recorded from San Juan, Guatemala, 
by G. C. Champion. In this same year it was discovered that the 
weevils were being introduced in cottonseed into the "Laguna" 
district in the State of Coahuila, Mexico, but effective measures were 
taken by the Mexican authorities, and the infestation was suppressed. 
Since that time the weevil has never been recorded from this impor- 
tant cotton region. The year 1903 is also important as being that 
in which the weevil first crossed the Sabine fuver into Sabine and 
Calcasieu Parishes in Louisiana. Another feature of the year was 
a large boll- weevil convention held at Dallas, Tex., which estab- 
lished a permanent organization and issued a number of valuable 
circulars relating to the problem. A similar meeting was held in 
New Orleans on November 30, at which the governor of the State 
presided. 

In 1904 a general realization of the great damage done by the 
boll weevil led to the appropriation by Congress of $250,000 for use 
in enabling the Secretary of Agriculture to meet the emergency 
caused by the ravages of the insect. It thus became possible again 
to increase the number of experimental farms and to pay especial 
attention to a number of important matters that could not be investi- 
gated previously. The large appropriation was used in part to estab- 
lish the demonstration work of the department. The object of this 
work was to demonstrate the methods of control perfected and 
demonstrated previously by the Bureau of Entomology. It has 
gradually developed into the well-known Farmers' Cooperative 
Demonstration Work of the Bureau of Plant Industry. 

With the advent of the weevil into Louisiana that State began 
energetic work against the pest. Largely through the efforts of 
Prof. W. C. Stubbs an extraordinary session of the legislature was 
convened early in 1904. The action decided upon was the estab- 
lishment of the Crop Pest Commission of Louisiana, with full authority 
to take such a course as might be found advisable. Prof. H. A. Mor- 
gan became secretary and entomologist of the commission. In 1905 
Prof. Morgan was succeeded by Mr. Wilmon Newell, who continued 
the cooperative investigations with the Bureau of Entomology 
throughout the period of his services in Louisiana, which extended 
to January 31, 1910. 

During 1904 two conventions were held at Shreveport, La. The 
first discussed especially the local features of the problem, while the 
second, which was held in November, was national in its scope. It 
was attended by delegates from most of the Southern States. 

The year 1904 witnessed an extensive dispersion of the weevil into 
new regions in Texas and Louisiana. During this year, Dr. O. F. 
Cook, of the Bureau of Plant Industry, found the weevil thoroughly 
established in Alta Vera Paz, Guatemala. 

At the beginning of 1905 the laboratory of the bureau was moved 
from Victoria to Dallas, Tex., where it has since remained. The 



ORIGIN AND HISTORY. 19 

observations on the activities of the boll weevil in this year were 
considerably limited, owing to restrictions on travel imposed by the 
yellow-fever quarantine. The insect was found, however, at Mazat- 
lan, State of Sinaloa, on the Pacific coast of Mexico, on March 20, 1905. 

In 1900 the weevil spread extensively to the west in Texas, a con- 
siderable distance northward into Oklahoma, into Arkansas, and 
almost to the Mississippi River in Louisiana. During this season Mr. 
M. T. Cook recorded the weevil from Santiago de las Vegas, Cuba, in 
addition to places previously recorded. 

The year 1907 marked the crossing of the Mississippi River into 
the State of Mississippi. There was a corresponding movement to 
the north, but none to the west. A very severe setback, caused by 
climatic conditions, occurred in the northern and western parts of 
the infested territory in November, 1907. 

In 1908 the most noticeable advances were made into Mississippi 
and Arkansas. By this time a considerable part of the Mississippi 
Delta region of Louisiana had become infested. 

In the spring of 1909 preparations were made for the establish- 
ment of a laboratory at Tallulah, La. The main object of this 
laboratory has been the accumulation of data concerning the local 
features of the weevil problem in the region where the greatest 
damage is certain to occur. Cold weather in the winter of 1908-9 
again checked the boll weevil so completely that it did no appre- 
ciable damage in Oklahoma and the greater part of Texas during 
1909. The checking of the insect was enhanced by the very unusual 
heat of July and August. However, there were enough weevils in 
the Red River Valley to give rise to a considerable movement into 
Arkansas and to a remarkable eastward movement in southern 
Mississippi which ended with a total advance of 120 miles eastward. 
This carried the insect to within 6 miles of the Alabama border. At 
the same time the decided climatic control of the season held the 
weevils in check in northern Louisiana so that the total advance in 
the Delta was little more than 20 miles northeastward. The year 
1909 closed with an exceptionally cold December which greatly 
reduced the numbers of the weevil in extreme northern Louisiana 
and in Arkansas, Oklahoma, and northern Texas. 

The winter of 1909-10 was probably more disastrous for the weevil 
than any it had previously experienced in this country. It was 
shown by examinations made in June and July, 1910, that the weevil 
had lost a very wide belt of territory in western Texas and that there 
was less than 1 per cent infestation in one-third of the infested region 
of Oklahoma and Texas. The reduction was also very pronounced 
in northern Louisiana and in the Mississippi Delta. In August it was 
found that there had been some recovery of lost territory, but there 
were still several thousand square miles of formerly infested territory 
in Oklahoma which the weevil had been unable to regain. There 
were slight gains in western Texas in the vicinity of Abilene late in 
the season and rather pronounced gains in the Delta region of Ar- 
kansas and in the hills of northern Mississippi and eastward through 
southern Mississippi and Alabama to the border of Florida. On 
account of the general scarcity of weevils the total amount of damage 
done during 1910 was less than had been experienced for several 
preceding years. 



20 THE MEXICAN COTTON-BOLL WEEVIL. 

An early frost on October 29, 1910, throughout all but the coast 
regions of the infested territory, caused the death of all but a very 
small fraction of the fall-bred weevils, and consequently the season 
of 1911 started with a low infestation. The general defoliation by 
the leaf worm, however, reduced the available food supply and caused 
a general dispersion, which enabled the weevils to regain considerable 
lost ground in Texas and Oklahoma, to make remarkable gains in 
Arkansas, Mississippi, and Alabama, and to invade Florida. 

DISTRIBUTION. 

The territory covered by the boll weevil at the end of the year 1911 
(see fig. 1) included the southeastern half of the cotton section of 
Texas, the southeastern corner of Oklahoma, the southern three- 

















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Fig. 1. Map showing the distribution of the cotton-boll weevil on January 1,1012. (Original.) 

fourths of Arkansas, all of Louisiana, the southern three-fourths of 
Mississippi, the southwestern corner of Alabama, and the western 
portion of Florida. In addition to these States the weevil is found 
throughout Mexico in the cotton-growing region of both the Atlantic 
and Pacific coasts with the exception of certain mountain regions. 
Foremost among the excepted regions is that known as theLaguna 
district in the vicinity of Torreon, Mexico. The weevil has not been 
recorded from any part of Yucatan excepting the western coast, 
although it may occur on tree cottons throughout this region. It 
has not been recorded from British Honduras, but is known to occur 
throughout the cotton regions of Guatemala and in Costa Rica. 
There is little doubt but that it also extends into other Central 
American Republics, although no definite records have ever been 



LOSSES DUE TO THE BOLL WEEVIL. 21 

made. The five western States of Cuba are infested, and possibly the 
weevil is to be found throughout the entire island. It has not been 
found in any of the other West Indian Islands. 

LOSSES DUE TO THE BOLL WEEVIL. 1 

Various estimates of the loss occasioned to cotton planters by the 
boll weevil have been made. In the nature of the case such esti- 
mates must be made upon data that are difficult to obtain and in the 
collection of which errors must inevitably occur. There is, of course, 
a general tendency to exaggerate agricultural losses as well as to 
attribute to a single factor damage that is the result of a combination 
of many influences. Before the advent of the boll weevil into Texas 
unfavorable weather at planting time, summer droughts, and heavy 
fall rains caused very light crops to be produced. Now, however, the 
tendency is everywhere to attribute all of the shortage to the weevil. 
Nevertheless, the pest is undoubtedly the most serious menace that 
the cotton planters of the South have ever been compelled to face, if 
not, indeed, the most serious danger that ever threatened any agri- 
cultural industry. It was generally considered, until the appearance 
of the pest in Texas, that there were no apparent difficulties to 
prevent an increase in cotton production that would keep up to the 
enlarging demand of the world until at least twice the present normal 
crop of about 12,000,000 bales should be produced. Now, however, in 
the opinion of most authorities, the weevil has made this possibility 
somewhat doubtful, although the first fears entertained in many 
localities that the cultivation of cotton would have to be abandoned 
have generally been given up. An especially unfavorable feature of 
the problem is in the fact that the weevil reached Texas at what 
would have been, from other considerations, the most critical time in 
the history of the production of the staple in the State. The natural 
fertility of the cotton lands had been so great that planters had 
neglected such matters as seed selection, varieties, fertilizers, and 
rotation, that must eventually receive consideration in any cotton- 
producing country. In general, the only seed used was from the 
crop of the preceding year, unselected, and of absolutely unknown 
variety, and the use of fertilizers had not been practiced at all. 
Although it is by no means true that the fertility of the soil had been 
exhausted, nevertheless, on many of the older plantations in Texas 
the continuous planting of cotton with a run-down condition of the 
seed combined to make a change necessary in order that the industry 
might be continued profitably. 

In 1905 Prof. E. D. Sanderson 2 made a very careful estimate of 
the damage done by the boll weevil in Texas for the six years ending 
with 1904. During this period he found that there had been an 
average annual decrease due to the boll weevil of 43 per cent, amount- 
ing to 0.182 bale per acre a year in the infected territory. 

Prof. Sanderson found that in 1899 the 18 counties infested at that 
time showed a decrease of 0.135 bale per acre, of which it was con- 
sidered that 150,000 bales were chargeable to the weevil. In 1900 
the great storm of September complicated matters so that no reliable 
estimate of injury could be made. In 1901 the general conditions 

i The following paragraph is modified from Bui. No. 51, Bureau of Entomology, pp. 21-25. 

3 The Boll Weevil and Cotton Crop of Texas, published by the Texas Department of Agriculture. 



22 



THE MEXICAN COTTON-BOLL WEEVIL. 



throughout the State were unfavorable to the cotton crop, resulting 
in a reduction of 0.05 bale per acre for the uninfested portion of the 
State. The weevil loss was estimated at 100,920 bales. In 1902 
the 32 counties infested produced 0.28 bale per acre. The loss 
chargeable to the boll weevil was 200,000 bales. In 1903 the 49 
counties infested yielded 0.23 bale per acre, as against an average of 
0.43 bale during years previous to infestation, which was interpreted 
to show a loss of 500,000 bales due to the weevil. In 1904, 69 counties 
were infested. These showed a loss of 0.22 bale per acre. This 
meant, after deducting the losses due to the bollworm and other 
causes, a loss of 550,000 bales due to the bol] weevil. In these esti- 
mates the losses for the period from 1899 to 1904 amounted to 
1,725,000 bales. 

The weevil was in Texas from 1899 to 1904, but had not caused 
any appreciable damage in Louisiana during that period. The 
statistics of production and acreage of the two States for these years 
show clearly the effect of the weevil on the crop. 

Table I. — Comparison of cotton -production and acreage in Texas and Louisiana in 
equivalents of 500-pound bales. 



Year. 


Texas. 


Louisiana. 


Acreage. 


Crop. 


Acreage. 


Crop. 


1899 


A cres. 
6,642,309 
7,041,000 
7, 745, 100 
8,006,546 
8,129,300 
8,704,000 


Bales. 
2,609,018 
3, 438, 3S6 
2, 502, 166 
2, 498, 013 
2,471,081 
3,030,433 


Acres. 
1,179,156 
1,285,000 
1,400,650 
1,662,567 
1,709,200 
1,940,000 


Bales. 
700, 352 
705, 767 


1900 


1901 


840, 476 


1902 


882, 073 


1903 


824,965 


1904 


893, 193 







It will be seen that while the acreage in Texas and Louisiana 
increased at about the same proportion the crop in Texas decreased 
annually for the six years ending with 1904 (with two exceptions — 
1900 and 1904), while the crop in Louisiana increased annually (with 
one inconsiderable exception, in 1903). That the boll weevil pre- 
vented Texas from keeping pace with Louisiana during this period 
will be admitted by all. The exceptional years, 1900 and 1904, in 
which the production in Texas did not decrease, were those in which 
the conditions for the cotton plant were unusually favorable. More- 
over, it is to be noted that in the first of these two years the pest had 
not reached far into the most productive counties. 

Further indications of the amount of weevil damage are available 
from the statistics of production per acre, as shown by Table II: 



Table II.- 


-Average yield per acre 


of cotton by five 


-year periods in 


500-pound bales. 


Years. 


Texas. 


Louis- 
iana. 


Arkan- 
sas. 


Okla- 
homa. 


Missis- 
sippi. 


1879 


Bale. 
0.39 
.37 
1.38 
1.39 
1.34 
1.32 


Bale. 

0. 58 

.51 

.52 

.52 

i .49 

' .29 


Bale. 

0.58 

.40 

.45 

.45 

1.40 

i .37 


Bale. 

0.48 

.48 

.52 

.47 

i.47 

' .35 


Bale. 
0.45 


1889 


.40 


1803-1 897 


.43 


1898-1902 


.40 


190: J- 1907... 






.44 


1908-1910... 






• .40 











i During these periods the weevil has caused more or less damage to the crop. 



Losses due to the boll weevil. 



23 



At 13 cents a pound for lint (average price in 1909) the 1908-1910 
average yields would mean an average loss from the average yield of 
1893-1897 of the following amounts per acre: 

Texas $3. 90 

Louisiana 15. 25 

Arkansas 5. 20 

Oklahoma 11. 05 

Mississippi 1 . 95 

Messrs. Norden & Co., of New York, have made a conservative 
estimate of the average annual loss in the various States, as follows: 

Per cent. 

Texas, about 15 

Louisiana 15 

Arkansas 15 

Mississippi 21 

The Bureau of Statistics of this department estimated the losses 
to the cotton crop in 1909 from various causes as shown below: 1 

Table III. — Amount of injury to cotton crop of l f J09 due to various causes. 





Loss in seed cotton per acre from— 


State. 


Climatic 
condi- 
tions. 


Boll 
weevil. 


Boll- 
worm. 


Other 
insects. 


Plant 
diseases. 


Miscella- 
neous 
causes. 


Total. 




Pounds-. 
112.2 
38.8 
103.3 
147.3 
100.4 


Pounds. 
21.5 
14S.8 
14.1 
11.0 
37.6 


Pounds. 
2.5 
8.5 
8.0 
3.7 
8.7 


Pounds. 
0.7 
1.3 
0.7 
0.4 
0.0 


Pounds. 
14.4 
11.0 
18.8 
2.2 
7.7 


Pounds. 
0.7 
1.4 
3.1 
3.4 
0.6 


Poundi. 
152.0 




209.8 




148.0 




168. 




155.0 






A verage of infested region . 


100.4 


46.6 


6.2 


0.6 


10.8 


1.8 


166.4 



According to tins estimate, the boll weevil was responsible for 
28 per cent of the loss in the five infested States and 14.9 per cent 
of the loss in the United States. This loss was estimated as 1 ,267,000 
bales of 500 pounds, which, at the current price of cotton in 1909, 
would be worth $88,056,500. Although the estimate of the Bureau 
of Statistics may be high, it was based upon the reports of numerous 
trained observers throughout the infested territory. 

Frequently misconceptions arise regarding the manner in winch 
the weevil has affected cotton production in Texas. This is due to 
the fact that the total crop of the State has been maintained more or 
less regularly since the advent of the pest. In order to obtain exact 
information on this point we must examine the statistics of produc- 
tion in different parts of the State. 2 

It is necessary to divide the State into three areas. These are 
eastern, central, and western Texas. The divisions are made in 
accordance with variations in normal annual precipitation and other 
factors. Eastern Texas as used in this bulletin is bounded on the 
west by a line running practically north and south from the western 

1 Crop Reporter, vol. 12, No. 12, p. 94, December, 1910. 

8 The following four paragraphs and table are extracted, with a few modifications, from Circular No. 122, 
Bureau of Entomology, pp. 5-8. 



24 



THE MEXICAN COTTON-BOLL WEEVIL. 



line of Lamar County to the western line of Brazoria County. In 
this region the rainfall is 45 inches per year or more. It comprises 
the counties listed below. 1 Practically the whole area is covered 
with forests. It covers 40,180 square miles. Central Texas com- 
prises a broad belt from the Gulf to the Red River, beginning on the 
west with the limit of the belt of 32 inches normal annual rainfall, 
and extends eastward to the line just described as defining the 
western boundary of the eastern Texas area. Central Texas consists 
of 45 counties 2 and comprises 38,868 square miles. 

It is for the most part prairie country, although there are wooded 
valleys and occasional strips of timbered uplands. Western Texas 
comprises the remainder of Texas, beginning with the line marking 
the western limit of the area of 32 inches normal annual precipita- 
tion. It is largely a prairie region, though wooded valleys are 
numerous. Another factor in differentiating western Texas from 
central Texas is the increased elevation. 

A careful study has been made of the manner in which the weevil 
has affected the production of cotton in the three regions mentioned. 
Use has been made of the Census records of production from 1899 to 
1910, a period of 12 years, as shown in Table IV: 

Table IV. — Eastern, central, and western Texas cotton production compared, 1899-1910 

from United States Census. 

[500-pound bales.] 





Eastern. 


Central. 


Western. 3 


Years. 


Bales. 


Propor- 
tion of 
Texas 
crop. 


Bales. 


Propor- 
tion of 
Texas 
crop. 


Bales. 


Propor- 
tion of 
Texas 
crop. 


1899 


637, 872 
811,413 
633,620 
736, 660 
545,288 


Per cent. 
22. 44 
23.59 
25.32 
29.48 
22.06 


1,033,618 
1,892,669 
1,448,872 
1,332,487 
1,242,654 


Per cent. 
62.01 
55.04 
57.90 
53.34 
50.28 


337,528 
734, 304 
419, 074 
428,806 
083, 139 


Per cent. 
12.94 


1900 


21.36 


1901 


16.77 


1902 

1903 


17.17 

27.64 






Average, 1899-1903 


672, 970 


24.88 


1,510,060 


55.85 


520, 702 


19 26 






1904 


720,671 
329, 523 
672, 497 
343,328 
515,038 
474,311 
645, 158 


22.91 
12.96 
16.11 
14.92 
13.50 
18.80 
21.15 


1,700,224 
1,414,115 
2,213,863 
1,218,143 
1,980,766 
1,362,096 
1,677,688 


54.15 
55.03 
53.03 
52.95 
50.00 
53.99 
55.02 


724,475 
79S, 294 

1,28", 840 
738, 708 

1,318,681 
686,404 
720,553 


23.07 


1905 


31.40 


1900 


30.85 


1907 


32.11 


1908 


33.08 


1909 


27.20 


1910 


23.83 






Average, 1904-1910 


528, 647 


17.19 


1,652,414 


53.02 


797,280 


28 88 









In eastern Texas the production for five years ending with 1903 
averaged 24 per cent of the total crop of Texas. During the same 
series of five years western Texas averaged 19 per cent of the total 

i Red Paver, Bowie, Franklin, Titus, Morris, Cass, Wood, Camp, Upshur, Marion, Harrison, Smith, 
Gregg, Cherokee, Husk, Panola, Nacogdoches, Shelby, San Augustine, Sabine, Angelina, Trinity, San 
Jacinto, Polk, Tyler ; Jasper, Newton, Liberty, Hardin, Orange, Jefferson, Chambers Galveston, Lamar, 
Delta, Hopkins, Rains, Van Zandt, Henderson, Freestone, Anderson, Leon, Houston, Madison, Waller, 
Grimes, Walker, Montgomery, Harris, Fort Bend, and Brazoria. 

2 Central Texas counties: Cooke, Grayson, Fannin, Denton, Collin, Hunt, Tarrant, Dallas, Rockwall, 
Kaufman, Johnson, Ellis, Bosque, Hill," Navarro, McLennan, Limestone, Bell, Falls, Williamson, Milam, 
Robertson, Brazos, Travis. Lee, Burleson, Washington, Hays, Bastrop, Caldwell, Fayette, Colorado, 
Austin, Guadalupe, Gonzales, Lavaca, Wharton, Dewitt, Goliad, Victoria, Jackson, Refugio, Calhoun, 
Matagorda, and Aransas. 

' Including counties grouped by Census under " All other." 



LOSSES DUE TO THE BOLL WEEVIL. 



25 



crop. For the seven years ending with 1910 the eastern Texas pro- 
duction dropped to 17 per cent of the total crop of the State, while the 
production in western Texas advanced to 28 per cent of the total 
crop of the State. In other words, the portion of the Texas crop 
produced in one area has decreased 21 per cent, and in the other it 
has increased 53 per cent. This increase in the west, where the dry 
climate reduces the boll-weevil injury, served to offset the loss in 
eastern Texas and thus accounts to a great extent for the fact that 
the total crop of the State has not fallen off. 

Mr. F. W. Gist, of the Bureau of Statistics of this department, has 
made a very careful study to determine the center of cotton produc- 
tion in Texas for each year from 1899 to 1908. As would be sup- 
posed from the figures that have been given, it was found by Mr. Gist 
that the center of production had moved considerably to the west- 
ward. In fact, this center moved from 30.78 miles east of the ninety- 
seventh meridian in 1899 to 19.14 miles west of this meridian hi 1908. 
This was a westward movement of practically 50 miles. The center 
of production in 1899 
was on a line passing 
north and south 
through the eastern 
Cortion of Grayson 
pountv, in Texas. In 
1908 the center had 
moved to a line pass- 
ing parallel with the 
other through the 
western portion of 
Cooke County, in 
Texas. These state- 
ments may be illus- 
trated by the follow- 
ing map (fig. 2). 

The statistics which 
have been given show 
the entire fallacy of 
attempting toestimate 
the seriousness of the 
boll-weevil problem by 

considering only the total crop which has been produced in Texas 
for some years past. It is absolutely necessary in estimating the 
damage that is likely to be done in any certain region to find the 
portion of Texas in which the climatic and other conditions are most 
like those in the region that is being considered. In Texas there are 
several very distinct boll-weevil problems due to local conditions, 
exactly as there are numbers of distinct agricultural provinces. The 
future of the boll weevil in the eastern part of the United States can 
not be foretold unless the manner in which the insect has affected 
the portion of Texas which is most like the eastern part of the belt 
is considered. An investigation of this matter will show that the 
eastern part of Texas is the only part of the State which is like the 
eastern portion of the cotton belt in the climatic and other features 
which react upon the boll weevil. This is especially the case with 




Fig. 2.— Map of portion of Texas, showing movement of the 
of cotton production westward. (Original.) 



26 THE MEXICAN COTTON-BOLL WEEVIL. 

reference to precipitation, the presence of timber, and temperature. 
It is clear, therefore, that the only criterion by which to judge the 
future damage of the weevil is the effect it has exerted on production 
in eastern Texas, where, as has been shown, there has been a consid- 
erable decrease in production. 

INDIRECT LOSSES CAUSED BY THE BOLL WEEVIL. 

The foregoing discussion has dealt altogether with the direct losses 
caused by the boll weevil, but it is to be noted that there are certain 
indirect losses which must be considered. It is not alone the farmers 
who are affected. The reduction in the size of the cotton crop imme- 
diately affects the ginning and oil-mill industries in which large 
amounts of money are invested. The railroads, banks, and mer- 
chants are also concerned. In fact, the disturbance extends through- 
out the community. In the case of many parishes in Louisiana one 
of the first results of the invasion of the boll weevil has been the 
reduction in the assessed valuation of farm lands. In all regions, for 
at least a short time, the price of farm properties has been reduced. 
Likewise in many localities the invasion of the insect has caused the 
exodus of large numbers of tenants and even of landlords. In the 
former case landowners have found themselves without the labor to 
run their places. Losses due to such disturbances can not be esti- 
mated, but it is safe to say that they reach an aggregate amount at least 
equal to the direct losses which are caused. 

COMPENSATIONS FOR LOSSES CAUSED BY THE BOLL WEEVIL. 

In spite of the great losses caused by the boll weevil it must be rec- 
ognized that certain compensations are returned. The insect forces 
a diversification of crops. There is no doubt that there is a tendency 
to place too much dependence in the South upon the cotton crop. 
When the ravages of the boll weevil reduce the size of this crop mate- 
rially or make production of a cotton crop hazardous, the farmers 
must change their system of cropping materially. This results 
directly in diversification and animal husbandry, and thus tends 
toward a more logical and profitable system of agriculture. Of course 
it would be much better if this change could be brought about by less 
revolutionary means and with less loss than is caused by the boll 
weevil. The tendency for many years has been toward diversification, 
which was certain to come in time. The boll weevil has undoubtedly 
hastened it and has thus in a broad sense offset, to a certain degree, 
some of the direct losses which it has caused. It is to be noted, how- 
ever, that in many cases this forced and, in one sense, premature 
diversification of crops has resulted disastrously. In some localities 
extensive and rapid growth has taken place in fruit raising and market 
gardening. In some of these instances the new industries have devel- 
oped with abnormal rapidity and without the proper foundation. 
This was the case in extensive plantings of potatoes made in 1909 by 
the cotton planters of Avoyelles Parish, La. The result has been 
that unless carefully managed the new lines of farming have failed 
and there has been a tendency to return to the cultivation of cotton. 

The boll weevil also tends to eliminate the indifferent and unprogres- 
sive farmer. He is driven either to the city or to some other locality. 



PROSPECTS. 



27 



In this way the weevil works toward the production of a better class of 
farmers. Of course, no community favors a reduction in the number 
of inhabitants. It would prefer that the inefficient remain and be 
improved by education or otherwise. This effect of the invasion of 
the boll weevil, therefore, can not generally be looked upon as a 
benefit. 

PROSPECTS. 

The rapid spread of the boll weevil in the past few years and its 
apparent adaptability to most of the conditions prevalent in the 
cotton region of the United States indicate that it will ultimately be 
able to exist in all except the semiarid portions of the entire cotton- 
growing country. In order better to estimate the probable move- 
ment in the future, we present Table V to illustrate its progress since 
the year 1892: 

Table V. — Annual movement of the boll weevil in the United States. 





Weevil advance. 


Total 
move- 
ment. 


Total 


Year. 


Texas. 


Louisi- 
ana. 


Okla- 
homa. 


Arkan- 
sas. 


Missis- 
sippi. 


Ala- 
bama. 


Flor- 
ida. 


area in- 
fested. 


1892.. 


Sg. mi. 

1, 400 

7,400 

10, 300 

7,900 

'7,300 

9,600 

7,200 

6,600 

6,600 

6,700 

11,600 

11,700 

39,600 

17,000 

22,600 


Sq. mi. 


Sq. mi. 


Sg. mi. 


Sq. mi. 


Sg. 771!. 


Sq. mi. 


Sq. mi. 
1,400 
7,400 
10,300 
7,900 
17.300 
9,600 
7,200 
6,600 
6,600 
6,700 
11,600 
12,000 
46, 900 
20,400 
36,600 
21,500 
18,500 
29,900 
14,200 
3,500 


Sg. mi. 
1,400 


1893 . . . 














8,800 


1894 














19,100 


1895 














27,000 


1896 .. 














19,700 


1897 














29,300 


1898 . 














36.500 


1899 














43,100 


1900 














49,700 


1901 














66, 400 


1902 . . 














68,000 


1903. . 


300 
7,300 
3,400 
9,300 
5,000 
5,700 
9,800 












80,000 


1904. . 












126,900 


1905 . 












147,300 


1906. . 


4,200 
8,200 
1,500 
1,900 
16,500 
13,000 


500 
7,800 
6,500 
7,500 
1,900 
9.700 








183,900 


1907 . . . 


500 
4,800 
10,700 
13,500 
11,000 






205. 400 


1908 . . 








223,900 


1909. ... 








253,800 


1910 


1,400 
J21.000 


3,900 
5,400 


1,400 


268,000 


1911 


271,500 






Total 


139,300 


40,800 


6,300 


31,900 


40,500 


9,300 


1,400 


271,500 









1 These figures indicate losses instead of gains. 

A summary of Table V in three-year periods is given below: 
Table VI. — Average annual rate of boll-weevil movement. 



Three-year periods. 


Total 
movement. 


Yearly 
average. 


Average of 
averages. 


1892-1894 


Sg. miles. 
19,100 
10,200 
20, 400 
30,300 
103, 900 
69,900 


Sq. miles. 
6,366 
3,400 
6,800 
10.100 
34,633 
23,300 


Sq. miles. 


1895-1897 




1898-1900 


5,522 


1901-1903 


1904-1906 




1907-1909 


22, 677 








253,800 




14,099 









At the end of 1910 the total area infested was 268,000 square miles, 
a net gain of 14,200 square miles over 1909. Including the year 1910, 
the average rate of movement in the United States besinnkie: with 



28 THE MEXICAN COTTON-BOLL WEEVIL. 

1904 has been 27,000 square miles a year, with 402,000 square miles 
of cotton-producing area ye't free. It is therefore reasonable to 
estimate that it will take at least 15 years before the entire cotton 
region of this country can become infested. 

It is evident, however, that the weevil will find certain definite 
checks in the cotton-growing regions of this country. Among the 
more important of these checks are (1) dryness, (2) low winter 
temperatures, (3) altitude, and (4) such combinations of these factors 
as tend to form definite life zones. The possible effects of these 
factors will be discussed separately. 

Dryness is the most important check the boll weevil experiences. 
The insect has repeatedly advanced into western Texas, but has 
invariably been prevented from gaining a foothold by the dry 
climate of that region. Occasional wet seasons have resulted in 
apparent gains in that quarter, but they have been nullified by the 
recurrence of normal years. The extremely dry conditions in 
Texas, Oklahoma, and Arkansas during the summers of 1909 and 
1910 had a remarkable effect upon the weevil. Combined with the 
very severe winters, these dry summers practically excluded the 
weevils from the western half of the infested region of Texas and 
most of the infested region in Oklahoma. The damage done in 
these regions for two seasons has occurred only after the breaking 
of the intense summer heat. The occasional occurrence of a dry 
summer, however, does not give any promise of future immunity 
from the boll weevil, because its tendency to disperse in the fall in 
all directions enables it to regain any ground which it might lose 
during such a season. It is also important to note that the practice 
of irrigation in dry regions may counteract the effects of the lack 
of precipitation and enable the weevil not only to maintain itself, 
but to cause considerable damage. 

The low temperatures of the winters of 1907, 1908, and 1909 had a 
very pronounced effect upon the numbers of the weevil in the follow- 
ing years. An analysis of the minimum temperatures reached in 
the regions where the weevils were most affected indicates that such 
control was the result of a temperature of 12° above zero. In some 
places where this temperature was reached there were earlier low 
temperatures which may have forced the weevils into considerably 
heavier shelter than they would have selected normally. This 
apparently enabled the weevils to survive even a temperature of 5° 
above zero. Although the information at hand is rather incomplete, 
we can nevertheless hold out some hope that regions having a mini- 
mum temperature of from 5° to 10° above zero will have little trouble 
from the boll weevil. In later sections of this bulletin we will show 
how even higher minimum temperatures can greatly reduce the weevil 
damage of the following year. The weakness of predictions of this 
kind is that they do not take into account the fact that the weevil is 
rapidly adjusting itself to changed conditions and that eventually the 
result of natural selection will be a class of weevils which can with- 
stand greater vicissitudes than those of the present. 

The extremely slow progress into western Texas might be explained 
on the basis of altitudes. So far, the weevil has not established itself 
at an altitude above 2,000 feet. It may be possible that this altitude 
is its extreme limit. Again, there is danger in this assumption, 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate II. 








The Boll Weevil and Insects Often Mistaken for it. 

a, The cotton boll weevil, Antkonomus grandis; b, the mallow weevil, Anthonomusfulvus; c, the 
southern pine weevil, Pissodes nemorensis; d, the cottonwood-flower weevil, Dorytomus 
mueidu*; e, Conotrachelus i rinaa us; /, the pecan ga\l\\evvi\.,Ojni>ti-w.iieluselegans. (Original.) 



INSECTS MISTAKEN TOR BOLL WEEVIL. 29 

because the boll weevil has shown considerable adaptability in the 
past and may be able to adapt itself to higher altitudes than it has 
jet reached. 

With regard to the possible relation between life zones and the 
distribution of the weevil it is to be said that at present the infested 
territory includes the tropical regions of Cuba, Central America, and 
Texas, and a considerable part of the Austroriparian Zone of the 
Lower Austral Region in the other Southern States. It is interest- 
ing to note that the weevil has not yet succeeded in establishing 
itself in the Upper Sonoran Zone of the Upper Austral Region of 
either Mexico or western Texas. It has invaded, or at least sur- 
rounded, two isolated areas of the Carolinian Zone of the Upper 
Austral Region in Oklahoma and Arkansas. Considerable cotton is 
grown in western Texas, in the Upper Sonoran Zone. There also 
exist in Arkansas, southern Missouri, Tennessee, northern Georgia, 
northern South Carolina, western North Carolina, and Virginia large 
regions of cotton-producing territory include* 1 in the Carolinian 
Zone. It is possible that the boll weevil will be unable to establish 
itself permanently beyond the limits of the Lower Austral Zone 
and this would exclude it from the regions just mentioned. 

As a matter of fact, the effects of climatic conditions upon the 
weevil are so powerful that there may be occasional diminution in 
the serious attacks from the insect in the moist regions, such as was 
experienced in the summer of 1911. The season of 191 1 was unusual 
in Louisiana and Mississippi, starting with severe cold in January, 
which cut down the emergence from hibernation to 0.5 per cent, 
and continuing with a very unusual drought. Such conditions are 
not often experienced, and we may usually expect severe attack by 
the weevil in southern Louisiana and the Delta of Mississippi. 

INSECTS OFTEN MISTAKEN FOR THE BOLL WEEVIL. 

The anticipated appearance of a serious pest such as the boll 
weevil in new regions causes greater attention to be given to the 
insects found in the cotton fields. Many planters notice common 
native insects which appear to answer the description of the boll 
weevil. The result of such mistaken identifications is generally a 
local panic. On account of the difficulty of distinguishing the boll 
weevil from a large number of related insects, we advise that whenever 
a planter discovers an insect which he suspects to be the boll weevil 
he send it either to the State entomologist or to the Bureau of Ento- 
mology and receive authoritative information. 1 



i Addresses of officials who will give authentic determinations of the boll weevil: 
Alabama.— \Y. E. Hinds, Auburn. 
A rkansas.— Paul Hayliurst , FayetteviUe. 
Florida.— E. W. Berger, Gainesville. 
(irorgia.—E. L. Worsham, Atlanta. 
Louisiana. — J. B. Garrett, Baton Rouge. 
Mississippi. — R. W. Harried, Agricultural College. 
North Carolina. —Franklin Sherman, jr., Raleigh. 
Oklahoma.— ■('. E. Sanborn, Stillwater. 
South Carolina.— A. P. Conradi, Clemson College. 
Tennessee..— G. M. Bentley, Knoxville. 

Texas. Wilmon Newell, College Station. Ernest Scholl, Austin, Department ol Agriculture. W. I>. 
Hunter, Bureau of Entomology, Dallas. 
Virginia.— E. A. Back, Blacksburg. 



30 



THE MEXICAN COTTON-BOLL WEEVIL. 



Many of the weeds in the vicinity of the cotton fields are attacked 
by different species of weevil's which may in some respects resemble 
the boll weevil. Some of these weevils are of a general dark color and 
have beaks with which to puncture their food plants. On close observa- 
tion it will be found that the weevils which are discovered on other 
weeds are breeding in those weeds. They are not the boll weevils 
and will not attack the cotton. Many of these native weevils are also 
found on the cotton plants at the nectar winch is produced by the 
squares, blooms, and leaves. These weevils simply visit the cotton 
plants in order to feed upon this nectar and do not injure the plant 
in any way. The following list contains the names and references to 
the habits of some of the most common weevils winch occur in and 
about cotton fields: 

Insects often mistaken for the boll weevil (Anthonomus grandis Boh.). (PI. II, a.) 



Weevil. 


Attacks. 


Anthonomus albopilosus Dietz 

Anthonomus eugenii Cano 

Anthonomus fulvus Le C. (PI. II, 6) 

Anthonomus signatus Say 

Anthribus cornutus Say 


Seed pods of wild sage (Croton). 

Pepper pods. 

Purple mallow buds. 

Blackberry, dewberry, and strawberry 

buds. 
Cotton stems. 


Arsecerus fasciculatus DeG 


China-berries, coffee beans, and old cotton 


Balaninus nasicus Say 

Balaninus victoriensis Chitt 


bolls. 
Acorns. 
Live oak acorns. 


Baris striata Say 


Roots of ragweed (Ambrosia). 

Roots of cockle-bur (Xanthium). 

Cowpea pods. 

Galls and nuts of pecans. 

Habits unknown. 

Stems of careless weed (Euphorbia). 

Acorns. 

Fruit of plums and peaches. 

Seed of sunflower (Helianthus). 


Baris transversa Say 

Chalcodermus seneus Boh 

Conotrachelus elegans Say (PI. 11,/) 

Conotrachelus erinaceus (PI. II, e) 

Conotrachelus leucophseatus Fab 

Conotrachelus naso LeO 

Conotrachelus nenuphar Hbst 

Desmoris constrictus Say 


Desmoris scapalis LeC 

Epicxrus imbricatus Say 

Gerseus penicellus Hbst 

Gerseus picumnus Hbst 


Flower heads of broad-leaved gum plant 

(Sideranthus). 
Cottonwood catkins. 
Habits unknown, adult feeds on foliage. 
Habits unknown, visits cotton nectar. 
Habits unknown, visits cotton nectar. 


Gerstssckeria nobilis LeC 

Hylobius pales Hbst 


Joints of prickly pear. 
Pine bark. 


IAxus scrobicollis Boh 

Pachylobius picivorus Germ 

Pissodes nemorensu Germ. (PI. II, c) 

Rhynchites mexicanus Gyll 


Stems of ragweed (Ambrosia). 
Pine branches and bark. 
Pine branches and bark. 
Rosebuds. 


Rhyssematus palmacollis Say 

Trichobaris mucorea LeC 


Morning-glory pods. 
Tobacco stalks. 


Trichobaris texana LeC 


Spanish thistle stalks. (Solarium ros- 
tra turn). 
Pods of false indigo (Baptisia). 


Tychius sordidus LeC 





Many other insects are sometimes mistaken for the boll weevil. 
This list includes only the species which are more or lesss closely 
allied to that insect and consequently more commonly confused 
with it. 



FOOD PLANTS. 31 

FOOD PLANTS OF THE BOLL WEEVIL. 1 

The careful investigations of Mr. E. A. Schwarz in Guatemala, 
Mexico, and Cuba have convinced him that the original food plants 
of the boll weevil are the tree cottons of those countries. One of 
these species has the seeds adhering together in a mass and is called 
"kidney" cotton from the shape of this mass. The other has seeds 
separated as in Upland cotton of the United States and is probably 
the Gossypium brasiliense of botanists. The former appears to be 
the more ancient form and presumably is the species upon which the 
weevil originally subsisted. Cotton is now rarely cultivated in Cuba, 
but the practically wild tree cottons are found throughout the island, 
and on these the boll weevil is generally to be found, although in 
very small numbers. There are, however, frequently found through- 
out the island isolated plants winch are not infested. The areas of 
cultivation of cotton in Guatemala are extremely isolated, but the 
presence of tree cotton perpetuates the weevil and gives it a rather 
general distribution. In Mexico the principal regions of cotton 
growth are represented by narrow belts along the two coasts and a 
large area in the north-central portion known as the "Laguna." 
Tree cotton probably serves to continue the boll weevil's activity in 
many parts of Mexico where cotton is not cultivated. It is impos- 
sible to decide whether the boll weevil originated in Cuba or in 
Central America, as it occurs in practically the same condition in 
both places. It is, however, practically certain that the insect has 
attacked the cotton plant from antiquity. In fact, there is notliing 
to indicate that it ever had any other food plant. 

The question of the possibility that the boll weevil may feed upon 
some plant other than cotton is one of importance. As an illustration 
we may state that as long as cotton is extensively produced in any 
given region there is comparatively little danger, but if a certain 
region should forego the planting of cotton for a period of years in 
order to escape boll-weevil injury and then resume its cultivation, it 
is apparent that all efforts would fail if the boll weevil could in the 
meanwhile exist on other native plants. 

It is a well-known fact that insects which have few food plants 
usually confine their attacks to closely related plants belonging to the 
same botanical family or even genus. The native plants most closely 
allied to cotton in the regions so far infested are the various species of 
Hibiscus and the trailing mallows of the genus Callirrhoe. Careful 
tests have been made with these plants and with many unrelated 
plants, both as to their powers of sustaining life and the inducements 
offered for oviposition. SLx species of Hibiscus, namely, esculentus, 
vesicarius, manihot, moscheutos, militaris, and africanus, have been 
tested to ascertain how long the weevil could live on them and whether 
it would oviposit in the fruit. In experiments conducted by Dr. W. E. 
Hinds hibernated weevils starved in an average time of about four 
days with leaves of either Hibiscus esculentus or II. militaris. Weevils 

• There has recently been discovered by Prof. C. H. T. Townsend another serious cotton pest, Antho- 
nomus vestilu.i Boheman, which we may designate as the Peruvian cotton square weevil, as it is not at pres- 
ent known outside of Peru and Ecuador. Prof. C. B. Banks has also discovered in the Philippine Islands 
a weevil feeding in cotton flowers which may be known as the Philippine cotton flower weevil. This species 
has been described as Ecthetopyga gossypii Pierce. The coffee-bean weevil, Arxcerus fasckulatus DeGeer, 
frequently breeds in old dried cotton bolls, and the cowpea pod weevil, Chalcodcrmus xneus Boheman, 
breeds occasionally in fresh cotton squares in fields of cotton following cowpeas. On account of the exist- 
ence of these other square and boll weevils it is still necessary to retain the original name Mexican cot- 
ton boll weevil for Anthonomus grandis Boheman. 



32 THE MEXICAN COTTON-BOLL WEEVIL. 

of the first generation which had fed upon no cotton were placed upon 
Hibiscus militaris, and these starved within an average of three or 
four days. The first-generation weevils which had fed for a few days 
on squares were placed upon leaves, buds, and seed pods of Hibiscus 
vesicarius. Though they fed a little, all starved in an average of about 
five days. A lot of first-generation weevils, fed first for several days 
with squares, were given leaves, buds, and seed pods of okra More 
feeding was done by this lot than by any other, all parts being slightly 
attacked. These weevils lived for an average of seven days. In 
experiments conducted independently by Messrs. Tucker and Jones 
at Alexandria and Shreveport, La., and Dallas, Tex., with II. mos- 
chuetos, H. militaris, and H. africanus, weevils were found to feed 
slightly on the pods, and fertile eggs were also found on the outside 
of the pods, but none were ever placed within. 

No results whatever were obtained by experiments with a species of 
Abutilon. In an experiment with hollyhock (Althsea sp.) three weevils 
lived an average of six days. In experiments by Mr. W. W. Yothers 
with buds of Callirrhoe involucrata, 42 weevils were fed for an average 
of 5.6 days, the maximum length of life being 1 1 days. These records 
show that the weevils may possibly be able to feed for a few days on 
some of the other malvaceous plants and that they may even be forced 
to oviposit, but that under present conditions they are unable to 
sustain life or to reproduce in these plants. The maximum length of 
life which they have been able to live on any of these plants is hardly 
greater than they could live with sweetened water (see Table XIII). 

Unsuccessful attempts were made to cause the weevil to feed upon 
sunflower (Helianihus annuus), bindweed (Convolvulus reports), the 
pigweeds (Amarantkus hybridus and A. sjrinosus), the ragweed 
(Ambrosia jjsilostachya) , and various other species of weeds and grasses 
which occur more or less frequently around cotton fields. 

Throughout the investigations of Prof. C. H. T. Townsend in 
southern Texas and Mexico and of Mr. E. A. Schwarz in Texas, Cuba, 
Mexico, and Guatemala, and the observations made by the writers 
and their associates in all the infested region of the United States, 
every plant closely related to cotton has been most carefully watched. 
The uniform failure to find the weevil feeding upon any other plant 
makes it practically certain that cotton is its only food plant. Of 
course, the insect sometimes alights upon other plants, as it does upon 
fence posts and other objects. Such occurrences are altogether acci- 
dental. Frequent reports of the finding of the weevil breeding in 
other plants are due to mistaking some other insect for the enemy of 
cotton. 

LIFE HISTORY. 

SUMMARY. 1 

The egg is deposited by the female weevil in a cavity formed by 
eating into a cotton square or boll. The egg hatches in a few days 
and the footless grub begins to feed, making a larger place for itself 
as it grows. During the course of its growth the larva sheds its skin 
at least three times, the third molt being at the formation of the pupa, 
which after a few days sheds its skin, whereupon the transformation 

i Extract from Bulletin 51, Bureau of Entomology, pp. 30, 31. 



j|. 1 14, Bureau of Entomology, U. S. Dcot. of Agriculture- 



Plate III. 




Anatomical Structure of the Boll Weevil. 

a, Dorsal view of anal segments of larva; b, front view of head and anterior segments of 
larva; c, ventral view of anal segments of larva; d, lateral view of adult; e, lateral view of 
larva; /, ventral view of adult; </, dorsal view of adult with wings spread; li, ventral view 
of pupa; /, ventral view of anal segments of pupa; j, ventral view of anterior portion of 
pupa. (Original.) 



DESCRIPTION. 33 

becomes completed. These immature stages require on the average 
between two and three weeks. A further period of feeding equal to 
about one-third of the preceding developmental period is required to 
perfect sexual maturity so that reproduction may begin. 

DESCRIPTION. 

THE EGG. 1 

The egg of the boll weevil is an unfamiliar object even to many 
who are thoroughly familiar with the succeeding stages of the insect. 
If laid upon the exterior of either square or boll, it would be fairly 
conspicuous on account of its pearly white color. Measurements 
show that it is, on the average, about 0.8 mm. long by 0.5 mm. wide. 
Its form is regularly elliptical, but both form and size vary somewhat. 
Some eggs are considerably longer and more slender t ban the average, 
while others are ovoid in shape. The shape may be influenced by 
varying conditions of pressure in deposition and the shape of the 
cavity in which it is placed. The soft and delicate membrane form- 
ing the outer covering of the egg shows no noticeable markings, but 
is quite tough and allows a considerable change in form. Were the 
eggs deposited externally they would doubtless prove attractive to 
some egg parasite as well as to many predatory insect enemies. 
Furthermore, the density of the membranes would be insufficient to 
protect the egg from rapid drying or the effects of sudden changes in 
temperature. All these dangers the female weevil avoids by placing 
the eggs deeply within the tissue of the squares or bolls upon which 
she feeds. As a rule, the cavities which receive eggs are especially 
prepared therefor and not primarily for obtaining food. Buried 
among the immature anthers of a square or on the inner side of one 
carpel of a boll, as they frequently are, weevil eggs become very in- 
conspicuous objects and are found, only after careful search. 

THE LARVA. 2 
(PI. Ill, a, 6, c, e.) 

The young larva, upon hatching from the egg, is a delicate, white, 
legless grub of about 1 mm. ( 2 V inch) in length. Except for the 
brown head and dark brown mandibles the young larva is at first as 
inconspicuous as the egg from which it came. As it feeds and grows 
it continues to enlarge a place for itself in the square or boll until the 
food supply has become exhausted or the vegetable tissues are so 
changed as to be unsuitable for food. By this time, as a rule, the 
interior of the square has been almost entirely consumed and the 
larval castings are spread thickly over the walls of the cavity. This 
layer becomes firmly compacted by the frequent turning of the larva 
as it nears the end of this stage. In the cell thus formed occur the 
marked changes from the legless grub to the fully formed and perfect 
beetle. 

Throughout this stage the body of the larva preserves a vent rally 
curved, crescentic form. The color is white, modified somewhat by 

1 Extract from Bulletin ")l , Bureau of Entomology, p. 31. 

« Extract from Bulletin 51 , Bureau of Entomology, pp. 34, 35. 

28873°— S. Doc. 305, 62-2 3 



34 THE MEXICAN COTTON-BOLL WEEVIL. 

the dark color of the body contents, which show through the thinner, 
almost transparent portions of the body wall. The dorsum is strongly 
wrinkled or corrugated, while the venter is quite smooth. The 
ridges on the dorsum appear to be formed largely of fatty tissue. 
After becoming full grown the larva ceases to feed, the alimentary 
canal becomes emptied, and both the color and form of the larva are 
slightly changed. The dark color disappears from the interior and 
is replaced by a creamy tint from the transforming tissues within. 
The ventral area becomes flattened, and the general curve of the 
body is less marked. Swellings may be seen on the sides of the 
thoracic region, and when these are very noticeable pupation will 
soon take place. 

THE PUPA. 1 
(PI. Ill, h, i,j.) 

When the pupal stage is first entered the insect is a very delicate 
object both in appearance and in reality. Its color is either pearly or 
creamy white. The sheaths for the adult appendages are fully 
formed at the beginning of the stage, and no subsequent changes are 
apparent except in color. The eyes first become black, then the 
proboscis, elytra, and femora become brownish and darker than the 
other parts. The pupa of the boll weevil can be distinguished 
readily from any other pupa which might be found in a cotton 
square or boll. Like all other curculionid pupa 1 , its beak rests on 
the venter of the body, with the legs drawn up at the sides and with 
the elytra on the dorsum as they will appear in the adult. But the 
boll-weevil pupa has two large quadrate tubercles on the prothorax, 
practically at the anterior apex of the body, and the abdominal 
segment which serves as the apex is produced in a rather chitinous 
flattened process, which is inflated at the middle and deeply quad- 
rately emarginate at apex, leaving only two strong acute teeth 
projecting. 

The final molt requires about 30 minutes. The skin splits open 
over the front of the head and slips down along the proboscis and 
back over the prothorax. The skin clings to the antennas and the tip 
of the proboscis until after the dorsum has been uncovered and the 
legs kicked free. Then by violently pulling upon the skin with the 
forelegs the weevil frees first the tip of the snout and then the anten- 
na?, and finally with the hind legs it kicks the shrunken and crumpled 
old skin off the tip of the abdomen. 

THE ADULT. 

(PI. II, a; PI. Ill, d,f,g.) 
BEFORE EMERGENCE. 

Immediately after its transformation from the pupa the adult is 
very light in color and comparatively soft and helpless. The proboscis 
is darkest in color, being of a yellowish brown ; the pronotum, tibiae, 
and tips of the elytra come next in depth of coloring. The elytra are 
pale yellowish, as are also the femora. The mouth parts, claws, and 

1 Modified and expanded from Bulletin 51, Bureau of Entomology, p. 38. 



DESCKIPTION. 35 

the teeth upon the inner side of the fore femora are nearly black. 
The body is soft, and the young adult is unable to travel, conse- 
quently this period is passed where pupation occurs. Usually two 
or more days are required to attain the normal coloring and the 
necessary degree of hardness to enable the adult to make its escape 
from the square or cell. 1 This is known as the teneral adult stage. 

DESCRIPTION OF ADULT. 

The following technical description of the species is taken from the 
Revision of Genera and Species of Anthonomini Inhabiting North 
America, by Dietz. 2 

Anthonomus grandis Boh. — Stout, subovate, rufo-piceous and clothed with coarse, 
pale-yellowish pubescence. Beak long, slender, shining, and sparsely pubescenl at 

the base; striate from base to the middle, striae rather coarsely punctured; apical 
half finely and remotely punctured. Antennae slender, second joint of funicle longer 
than the third; joints 3-7 equal in length, but becoming gradually wider. Head 
conical, pubescent, coarsely Tout remotely punctured, front foveate. Eyes moder- 
ately convex, posterior margin not free. Prothorax one-half wider than long; base 
feebly bisinuate, posterior angles rectangular; sides almost, straight from base to mid- 
dle, strongly rounded in front; apex constricted and transversely impressed behind 
the anterior margin; surface moderately convex, densely and subconfluently punc- 
tured; punctures irregular in size, coarser about the sides; pubescence more dense 
along the median line and on the sides. Elytra Oblong, scarcely wider at the base 
than the prothorax; sides subparallel for two-thirds their length, thence gradually 
narrowed to and separately rounded at the apex, leaving the pygidium moderately 
exposed; striae deep, punctures large and approximate; interstices convex, rugulose, 
pubescence somewhat condensed in spots. Legs rather stout, femora clavate, ante- 
rior strongly bidentate, inner tooth long and strong, outer one acutely triangular 
and connected with the former at the base; middle and posterior thighs unidentate. 
Tibiae moderately stout, anterior bisinuate internally, posterior straight; tarsi moder- 
ate, claws broad, blackish, and rather widelv separate; tooth almost as long as claw. 
Long. 5-5.5 mm.; 0.20-0.22 inch. 

SIZE OF WEEVILS. 

The size of boll weevils is somewhat variable. It varies almost 
directly in proportion to the abundance of the larval food supply and 
the length of the period of larval development. It also depends 
upon the nature of the food, whether it is squares or bolls. 3 The 
smallest weevils are developed from squares which are very small, 
and which, for some reason, either of plant condition or of additional 
weevil injury, fall very soon after the egg is deposited. In such cases 
the supply of food is not only small, but possibly, owing to the imma- 
turity of the pollen sacs, its quality is poor. Normally, squares con- 
tinue to grow for a week or more after eggs are deposited in them, 
and such squares produce the weevils of average size and color. 

The largest weevils are produced in bolls which grow to maturity. 
In them the food supply is most abundant, and the period of larval 
development is several times as long as it is in squares. Weevils 
reared from squares late in the season, where infestation has reached 
its maximum, are of small size, whereas weevils reared from large 
bolls are very noticeably larger. The extremes are so great that the 
largest and smallest weevils would be thought, by one not familiar 

1 The foregoing is extracted from Bulletin 51, Bureau of Entomology, p. 39. 

* Trans. Amer. Ent. Soc, vol. 18, p. 205. 

3 The following sentences are taken from Bulletin 51, Bureau of Entomology, p. 11. 



36 



THE MEXICAN COTTON-BOLL WEEVIL. 



with them, to be of entirely different species. So far as dimensions 
may convey an idea of the size, we may say that the weevils range 
from 2.5 mm. to 6.75 mm. (fa to £ inch) in length, measuring from 
base of beak to apex of elytra, and from 1 mm. to 3 mm. (fa to | 
inch) in breadth at the middle of the body. 



WEIGHT OF WEEVILS. 



A number of interesting observations have been made at various 
times upon the weight of weevils in connection with the nature of the 
food supply. These observations have been tabulated, as follows: 

Table VII. — Weight of boll weevils from different sources. 



Source. 


Condition 
when weighed. 


Number. 


Average 
weight. 




Fed 


25 
08 
3C 
9 
15 
69 


Grains. 
0. 105 




do 


.231 


Do 


Unfed 


.102 


Do 


Fed .. 


.110 




....do 


.OSO 




....do 


.268 








Total 


222 














.192 











COLOR OF WEEVIL. 

Color is very often a variable character in insects, and the boll 
weevil presents considerable range in this respect. Normally, the 
general color becomes darker with age. Consequently, hibernated 
weevils are the darkest found, but another factor must be considered. 
As has been noted, whatever influences the size of the larva affects 
directly the size of the adult, and it is noticeable that weevils of the 
same size are also, as a rule, similar in color. In general, the smaller 
the size of the weevil, the darker brown is its color; the largest weevils 
are light yellowish brown. Between these two extremes are the 
majority of average-sized weevils, which are either of a gray-brown 
or dark yellow-brown color. In the opinion of Dr. W. E. Hinds 
the principal reason for the variation in color lies in the degree of 
development of the minute, hair-like scales, which are much more 
prominently developed in the large than in the small specimens, 
although the color of old specimens is often changed by the abrasion 
of the scales. These scales are yellow in color, while the ground 
color of the chitin bearing them is a dark brown or reddish 
brown. The development of the scales appears to take place mostly 
after the adult weevils have become quite dark in color, but before 
the chitin becomes fully hardened. They seem, therefore, to be, to 
a certain extent, an aftergrowth which depends upon the surplus 
food supply remaining after the development of the essential parts 
of the weevil structure. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IV. 




The Adult Boll Weevil and Emergence Holes. 

a. Squares of Peruvian cotton, showing emergence holes of the Peruvian cotton-square weevil; 
b, square of upland cotton, showing emergence hole of the cotton-boll weevil; c, adult boll 
weevil on cotton square; d, adult boll weevil puncturing cotton square; e, adult boll weevil 
emerging from cotton boll; /, small dry bolls, showing emergence holes; g. hull of boll, with 
weevils found hibernating. (Original.) 



DESCRIPTION. 



37 



SECONDARY SEXUAL CHARACTERS. 

We are indebted to Dr. A. D. Hopkins, of the Bureau of Entomology 
for indicating the most strongly marked points of difference in the sec- 
ondary sexual characters of the boll weevil. (See fig. 3.) The dis- 
tinctive characters are found upon the snout and upon the last two 
abdominal segments. The differences are subject to some variation, 
but are still sufficiently constant to enable a close observer with the 
aid of a hand lens positively to differentiate males from females. 

Female. The snout of the female is slightly longer and more 
slender than that of the male. When viewed from above it usually 
appears to taper slightly from each end toward the middle. The 
antennae are inserted slightly farther from the tip than is the case in 
the male. The insertion is at about two-fifths of the distance from 
the tip of the snout to t he eyes. As a rule the surface of the snout is 
more smooth and shining than in the male. A slight depression, 





v /7V & fe' 7 <7fh,0-38m77i. } f//>to//7serf/of? ? O./2m/7i: 
~^- {'^f/ O 77 0.42 7* n 9 7? 0./8 » 

S ^ -pffOPYG/D/UM" "^ ^jZ^ + 
^PYG/D/UM--~~~ 6 

Fig. 3. -Secondary sexual characters of Anthonomus grandis. (From Bind and Yothers, aftei Hopkins.) 

rather elongated and much larger than any of the other punctures 
upon the snout, occurs between the bases of the antenna 1 . When the 
wing covers and wings are unfolded the abdomen shows seven distinct 
dorsal segments. The last segment visible in the female, called the 
propvgidrum, can be seen only from the sides. 

Mate. — In the male the snout is slightly shorter, thicker, and more 
coarsely punctured than in the female. The depression mentioned in 
the female is lacking. The antenna 1 are inserted at practically one- 
third of the distance from the tip of the snout to the eyes. The sides 
of the snout are very nearly parallel. In the abdomen the male shows 
eight distinct dorsal segments, the terminal segment (pygidium) not 
bemg covered by the propygidium as is the casein the female. 

In general practice an examination of the beak is sufficient to deter- 
mine the sex of each weevil. 



1 This discussion id modified from Hull. 77, Bureau of Entomology, pp. 91, 92. 



38 THE MEXICAN COTTON-BOLL WEEVIL. 

SEASONAL HISTORY. 

THE ADULT WEEVIL. 

EMERGENCE. 1 

(PL IV, b, e; PI. Xl,e,f.) 

The adult boll weevil's normal method of escape from squares and 
small bolls is by cutting with its mandibles a hole just the size of 
its body. In large bolls the escape of the weevil is greatly facilitated 
by the natural opening of the boll. Often the pupal cell is broken 
open by the spreading of the carpels, and when tins is the case the 
pupa, if it has not already transformed, becomes exposed to the attack 
of enemies or, what is probably a more serious menace, to the danger 
of drying so as seriously to interfere with a successful transformation. 
If the cell remains unbroken the weevil always escapes by the path 
of least resistance, cutting its way through as in the case of a square. 

CHANGES AFTER EMERGENCE. 2 

At the time of emergence the weevils are comparatively soft, and 
they do not attain their final degree of hardness for some time after 
they have begun to feed. The chitin is of an orange tinge at the time 
the weevils leave the squares or bolls, but after exposure for some 
time it turns to a dark chocolate brown. 

PROTECTIVE HABITS. 

Not only is the boll weevil protected from its enemies by its color, 
which resembles both the dry squares and also the pulverized soil 
upon which it frequently drops, but it has a protective habit, found 
more or less commonly among insects. At the first disturbance of 
the cotton plant, or sometimes even at a movement of a large object 
in the vicinity of the cotton plant, the boll weevil becomes very alert, 
raising its antennae and standing almost motionless. If the disturb- 
ance continues, the weevil falls to the ground with its legs drawn up 
close to the body and the antenna? retracted against the beak, which 
is brought inward toward the legs. In this position it often remains 
motionless for some time, but if further disturbed, it will start up 
quickly, run a short distance and again fall over, feigning death. 
This habit is popularly known as "suiting" 3 or "playing possum." 
Frequently, in falling, the weevil comes in contact with some part 
of the plant and immediately relaxes and takes shelter on the plant, 
or sometimes it spreads its wings and flies away instead of falling 
to the ground. In July and August the weevils become more alert 
than at any other season of the year, and flight more frequently 
follows the dropping from the plants. 

FOOD HABITS. 

Before escaping from the square the adult empties its alimentary 
canal of the white material remaining therein after the transformation. 
The material removed in making an exit from the cell is not used as 

1 E stracted from Bull. . r >l , Bureau of Entomology, pp. 39, 40. 
s Extracted from Bull. 51, Bureau of Entomology, p. 40. 
8 Undoubtedly a corruption of "sulking." 



SEASONAL HISTORY. 



39 



food, but is cast aside. Weevils are ready to begin feeding very soon 
after they escape from the squares or bolls in which the previous 
stages have been passed. For several days thereafter both sexes 
feed almost continuously. They much prefer squares, but in con- 
finement will feed upon leaves, flowers, or bolls. Under natural 
conditions any portions of the plants other than the squares and bolls 
are seldom attacked. The bolls are only slightly attacked so long as 
there is an abundance of uninfected squares. 

x The method of feeding is alike in both sexes. The mouth parts 
are very flexibly attached at the tip of the snout (fig. 4) and are 
capable of a wide range of movement. The head fits smoothly into 
the prothorax like the ball into a socket joint and is capable of a con- 
siderable angle of rotation. The proboscis itself is used as a lever in 
prying, and helps to enlarge the puncture through the floral envelopes 
especially. Feeding is accomplished by a combination of movements. 
The sharply toothed mandibles serve to cut and tear, while the rota- 
tion of the head gives the cutting parts an auger-like action. The 
forelegs especially take a very firm hold upon the square and help 
to bring a strong pressure to bear upon the proboscis during certain 
portions of the excavating process. The 
outer layer of the square, the calyx of the 
flower, is naturally the toughest portion that 
the weevil has to penetrate, and only enough 
is here removed to admit the snout. After 
that is pierced the puncture proceeds quite 
rapidly, combinations of chiseling, boring, 
and prying movements being used. While 
the material removed from the cavity is used 
for food, the bulk of the feeding is upon the 
tender, closely compacted, and highly nutri- 
tious anthers or pollen sacs of the square. 
When these are reached the cavity is en- 
larged, and as much is eaten as the weevil 
can reach. The form of the entire puncture 
becomes finally like that of a miniature flask. 

Only after weevils have fed considerably 
do sexual differences in feeding habits begin 
to appear; from this time on the females puncture mainly the base 
and the males the tip of the square. 

Feeding punctures are much larger and deeper than are those made 
especially for the reception of the eggs; more material is removed 
from the inside of the square or boll and the opening to the cavity is 
never intentionally closed. Feeding punctures are most frequently 
made through the thinner portion of the corolla not covered by the 
calyx. The exposed tissue around the cavity quickly dries and turns 
brown from the starting of decay. As a number of these large cav- 
ities are often formed in one square (PI. V, c), the injury becomes so 
great as to cause the square to flare immediately, often before the 
weevil has ceased to feed upon it. Squares so severely injured fall 
in a very short time. The injury caused by a single feeding puncture 
is often overcome by the square, which continues its normal course 
of development. When feeding punctures are made in squares which 
are nearly ready to bloom, the injury commonly produces a distorted 




Fig. 4.— Cotton-boll weevil: Head, 
much enlarged, showing rostrum, 
with antennae near middle and 
mandibles ai end; mandible, 
more enlarged, at right. (Orig- 
inal.) 



» The following four paragraphs are borrowed from Bulletin 51, Bureau of Entomology, pp. 50, 51. 



40 



THE MEXICAN COTTON-BOLL WEEVIL. 



bloom (PI. V, e, j), and in very severe cases the boll will drop soon 
after setting. 

After the females begin to oviposit their feeding habits become 
quite different from those of the males. Up to this time both sexes 
move but little, making a number of punctures in a single square; 
but from this point we must consider the feeding habits of the sexes 
separately. 

Males puncture the tip portion of the square not covered by the 
calyx more often than do the females. The yellow or orange colored 
excrement is abundant, and owing to the somewhat sedentary habits 
of the males it accumulates often in rather large masses, so that it is 
often possible to tell whether a square in the field has been attacked 
by a male rather than by a female weevil. Observations made by 
Dr. Hinds on 70 specimens under both field and laboratory conditions 
show that for the first few days of their life the males make from six 
to nine punctures a day, but that during their entire life they average 
about 1.2 punctures per day and an average of 2.6 punctures per 
square, injuring only about two squares every three days. Whether 
in or out of doors, the activity of feeding decreases as the male 
becomes older. 

After they begin to oviposit females seem generally to feed less 
upon one square or in one puncture than they do previous to that 
time. They obtain quite a considerable portion of their food from 
the excavations which they make for the deposition of their eggs, and 
as they show a strong inclination to oviposit only in clean or pre- 
viously uninfested squares their wandering in search of such squares 
keeps their punctures scattered so long as plenty of clean squares 
can be found. When clean squares become scarce, the normal incli- 
nation can not be followed, and the number of punctures made in 
each square will be greatly increased. 

Table VIII is presented to illustrate the feeding activity of both 
sexes : 

Table VIII. — Rate of making egg and feeding punctures by the l>nJl weevil. 1 





Num- 
ber 

of 
males. 


Num- 
ber 
of fe- 
males. 


Total. 


Average. 


Character of lot. 


Weevil 

days. 


Feed- 
ing 
punc- 
tures. 


Egg 
punc- 
tures. 


Feeding 

punctures 
per weevil 

day. 


Egg pimc- 

turi's per 

female 

day. 


Period of 

observa- 
tion. 


Hibernated weevils in 


55 
31 


54 

27 

■1 

5 


4,938 

3,258 

93 

70 

2,492 

145 


17,400 

16, 487 

284 

203 

5,017 

177 


5,702 

3,565 

489 

435 


+3.5 

+5.0 

+3.0 

-3.8 

-2.3 

1.2 


+2.3 
-2.4 
-5.3 

+0.2 


Days. 

+ 45.3 


Weevils of first genera- 
tion in laboratory 

Hibernated females in 


-50.2 
—23.3 


First -general ion females 




14.0 


Males in laboratory 


lio 
5 


+3X. 3 




+29.0 








Total 


156 


90 


10.990 


40. 234 


10,191 










3.6 


2.4 


44.7 

















1 Modified from Bulletin 51, Bureau of Entomology, p. 52. 



Bui. 1 14, Bureau of Enton 



U. S. Dept. of Agricultur 



Plate V. 




Effects of Boll-Weevil Attack on Leaf and Squares. 

a, Cotton leaf much fed upon by adults: b, square with two egg punctures; c, flared square with 
many feeding punctures; d, square prevented from blooming by puncture: e, bloom injured 
by feeding punctures; /, poor blooms caused by feeding punctures. (Original.) 



SEASONAL HISTORY. 41 



ABILITY TO LOCATE COTTON. 



When hibernated weevils emerge from their winter quarters in 
search of food they are frequently long distances from the nearest 
cotton field. It has been a question of considerable interest whether 
the weevils are able to locate cotton or whether they find it by chance. 
Dr. A. W. Morrill conducted a series of experiments in the laboratory 
to test the attraction of cotton squares for the weevil, but the results 
were not conclusive. In the eight years of study of the boll weevil, 
there have been very few records of weevils on any other plants than 
cotton, notwithstanding the fact that special collections wore made 
in the woods and fields near the cotton fields in search of boll weevils. 
In the season of 1905 extensive collections were made by means of 
sweeping nets by several men for weeks during the dispersion season, 
and yet not a single weevil was found outside of the cotton fields. 
All oi this would indicate that there is some attraction of the weevils 
to cotton. The concentration of weevils upon the earliest plants in 
the spring and upon the greenest and most luxuriant portions of the 
fields in the fall are also evidences of the ability of the weevils to 
find desirable places for feeding. 

FEEDING HABITS OP HIBERNATED WEEVILS. 

Whether there be few or many hibernated weevils makes no differ- 
ence in their feeding habits. The stage of the cotton at the date of 
emergence determines largely the nature of the food habits at that 
time. The first weevils to emerge obtain their food from the tender, 
rapidly growing, terminal portions of the young plants. They place 
themselves upon the node where the two cotyledons branch. In fact, 
this seems to be the point usually attacked in cases of very young 
cotton plants. In almost all cases the puncture of the weevil at this 
point results in the death of the plant. Sometimes the attack is 
made a little above the node on a petiole of the cotyledon, in which 
case the one cotyledon falls and the other remains, and the plant 
usually recovers. However, it frequently happens that the same 
weevil attacks both of the cotyledons. This form of attack is fatal 
to the seedlings unless they have become very vigorous — sometimes 
until they have developed two true haves. Later the central bud, 
young leaves, or tender stems are attacked, and upon these the weevils 
easily subsist until the squares are developed. (See PI. V, a.) In cases 
where the emergence from hibernation is very large the weevils may 
come out in such numbers upon the newly sprouted cotton as to 
stunt or even kill the growing plants by their depredations upon the 
terminal portion. 

Weevils which have fed upon tender tips of plants seem perfectly 
satisfied with their food supply, and it appears that their first meal 
upon squares is largely the result of accident. After having begun 
to feed upon squares, however, it appears that their taste becomes 
so fixed that they normally seek for squares. 

In the spring of 1895 Mr. E. A. Schwarz found the first emerged 
hibernated weevils working upon plants which had sprung from 
2-year-old roots. In the spring of 1903 in one field of comparatively 
early cotton, 2 or 3 acres in extent, the senior author found, between 
April 24 and May 11, 23 weevils working on the buds and tender 
leaves of stubble plants before a single weevil was found on the 



42 THE MEXICAN COTTON-BOLL WEEVIL. 

young planted cotton having from four to eight leaves. At Victoria, 
early in June, 1902, Mr. A. N. Caudell found, in examining 100 
stubble plants growing in a planted field, that fully one-half of the 
squares upon these plants were then infested. The planted cotton 
was just beginning to form squares and was slightly injured at that 
time. 

It appears, therefore, that stubble plants, where such exist, 
receive a large part of the first attack of the hibernated weevils, 
not because of any special attraction, but for the reason that they 
are present long before the planted cotton has come up. The 
occurrence of volunteer and stubble cotton in the fields in the early 
spring is of considerable importance in the boll- weevil problem. 
Tliroughout the coast regions, especially of southern Texas, stubble 
cotton is very common in the fields, and there is hardly a region 
of the South where volunteer cotton can not be found before the 
normal planting is up. (See PI. VIII, a.) 

It is by no means certain that all or even a large proportion of 
the hibernated weevils may be found upon the early plants, and this 
renders their use as traps entirely impracticable. A number of 
observations have shown that weevils frequently occur upon the 
planted cotton, even when numbers of vigorous stubble plants may 
be found within a comparatively short distance. In fact, at Victoria, 
Tex., in 1904, many weevils were found feeding upon the planted 
cotton for more than six weeks after the stubble plants were producing 
fruit. 

DESTRUCTIVE POWER BY FEEDING. 1 

A glance at the figures in Table VIII is sufficient to show the 
great destructive power of the Mexican cotton-boll weevil. It may 
be seen that both in the field and in the laboratory the weevils of 
the first generation are more active in making punctures than are 
the hibernated weevils. These generations overlap too far to justify 
us in attributing this difference to the influence of a higher temper- 
ature alone, though this factor will account for a large part of it. 
A comparison of the figures for males alone with those for females 
alone or with those for males and females together shows that it is 
very conservative to state that males make less than half as many 
punctures as do females. By the habit of distributing their punc- 
tures among a greater number of squares the destructiveness of 
the females becomes at least five times as great as that of the males. 

This great capacity for destruction has been one of the most 
evident points in the history of the spread of the weevil and has deeply 
impressed the entomologists who first studied the insect in Texas. 
In 1895 Mr. E. A. Schwarz, in writing of the work of the weevil at 
Beeville, said : 

Each individual specimen possesses an enormous destructive power and is able to 
destroy hundreds of squares, most of them by simply sticking its beak into them for 
feeding purposes. 

ATTRACTIVENESS OF VARIOUS SUBSTANCES. 

Experiments have proved that the report which has sometimes been 
circulated to the effect that cottonseed meal attracts the weevil is due 
to mistaking other insects for it. Many tests, both in the laboratory 

1 Extracted from Bulletin 51, Bureau of Entomology, p. 61. 



SEASONAL HISTORY. 



43 



and in the field, have shown that sugar and molasses, either in solution 
or otherwise, have no attraction whatever for the weevil. Honey 
exerts a very weak attraction, but not enough to be of any practical 
use in control. In fact, it has not been found that any substance 
exerts a special attraction for the weevil. The experiments have dealt 
with many chemicals as well as plant decoctions. 



SENSE OF COLOR. 



A series of interesting observations on the color sense of the boll 
weevil was made by Mr. C. R. Jones at Calvert and Victoria, Tex., and 
Alexandria, La., in 1907. Tubes of different colors were placed in a 
box, all with an equal amount of sunlight, and the weevils were given 
food. The observations were made at intervals during the day, and 
each time the weevils were all shaken back into the box. Table IX 
shows the total number of weevils found at each color for the series of 
observations and also the weighted average attractiveness. Fourteen 
shades were used, but these may be grouped under eight colors. The 
three most attractive shades were light-blue, dark-green, and light- 
pink. While it is rather difficult to explain the results, it nevertheless 
appears that there is some preference for certain colors on the part of 
the weevil. 

Table IX. — Relative attractiveness of colors to the boll weevil. 



Color. 



Blue. 
Green. 
Yellow 

Hod... 
While. 
Purple. 
Orange 
Black.. 



Number of 


Number 


observa- 


of weevils 


tions. 


attracted. 


64 


461 


43 


261 


32 


123 


107 


411 


11 


24 


32 


29 


10 


5 


21 


ti 



Average 

al irartivc- 
ness. 



Per ctnt. 

7.2 

6.0 

3.8 

3.8 

2.1 

.8 

.5 

.2 



MOVEMENTS ON POOD PLANT. 



Various observations have been made to determine the amount of 
movement of weevils at night. In July, 1904, at a mean temperature 
of 76.3° F., Mr. A. C. Morgan found," in an aggregate of 134 weevil 
nights, that eight weevils had moved but 25 times. Each weevil 
had moved only once every six nights. On cloudy days weevils are 
much more sluggish than on sunny days. Relative humidity influ- 
ences the activity, but no definite observations on this point have been 
made. 

The effect of temperature on locomotive activity may well be illus- 
trated by a series of laboratory experiments conducted by Dr. A. W. 
Morrill. A thermometer was passed through a cork and inclosed in 
a test tube, which in turn was placed within a hydrometer cylinder 
of sufficient deptli to inclose it. Weevils were inclosed in the test tube 
with the thermometer, and the temperature of the cylinder was varied 
either by heating gently or by the use of ice water. St arting with the 
thermometer at 64° F., the 10 weevils inclosed were found to move 
slowly, half of them being quiet. As the temperature was gradually 



44 



THE MEXICAN COTTON-BOLL WEEVIL. 



raised the activity of the weevils increased up to 105° F. When the 
temperature reached 95° F. or over the weevils were running up 
and down the tube. By tilling the cylinder with cold water the 
temperature was lowered to 86° F., at which point the weevils began to 
cluster at the top on the cork and were crawling slowly. By the 
addition of ice in the cylinder the temperature was lowered to 59 F., 
at which point five weevils were struggling on the bottom of the test 
tube or clinging to one another, four were clustered on the stopper, 
while one was slowly crawling downward. At 50° F. six weevils 
at the bottom showed slight signs of life, and one was crawling 
slowly. At 45.5° F. slight signs of life were still shown, while at 
40° F. occasional movements only were noted. When the tempera- 
ture was raised weevils began crawling as 50° F. was passed, and at 
64° all had left the bottom and were crawling upward. Some recov- 
ered more quickly than did others. The temperature was again 
lowered, this time by the use of salt with ice. All movement ceased 
at 37° F. The cooling, however, was continued to 33° F., after 
which it was slowly raised to 42° F., at which point movements began. 

EFFECTS UPON SQUARES AND BOLLS OF FEEDING BY THE BOLL WEEVIL. 

From numerous large, open feeding punctures a square becomes so 
severely injured that it flares very quickly, often within 24 hours. 
(See PI. V, c.) Males usually make the largest punctures, which they 
always leave open while they remain for a day or more working upon 
the same square. It has been often found that squares thus injured 
by a male will flare before the weevil leaves it. The time of flaring 
depends upon the degree of injury and the size of the square. Thus 
small squares winch receive only a single large feeding puncture in 
the evening are found widely flared in the morning. On the other 
hand, large squares which are within a few days of the time of their 
blooming may receive a number of punctures without showing any 
noticeable flaring. Frequently a square which has flared widely will 
be found later to have closed again and to have formed a distorted 
bloom, and occasionally such squares develop into normal bolls. 
(See PI. V, e, f.) In squares of medium size a single feeding punc- 
ture does not usually destroy the square. The destruction of a 
square by feeding results either from drying or decay which follows 
the weevil injury. 

Table X. — Destruction of squares by the feeding of the holl weevil. 



Period. 



Juno-July 

August-September. 
< ictober-November. 

Total 

Weighted averages. . 



Total 
number of 

squares 
punctured. 



751 
426 
176 



1,353 



Number of 

squares 

with 

feeding 

punctures. 



170 
183 

74 



Total 
number of 

feeding 
punctures. 



335 
383 
210 



934 



Average 
number of 

feeding 
punctures 
per square. 



1.9 
2.0 
2.9 



2.0 



Average 
number of 
days before 

falling. 



5.8 
4.4 
15.2 



7.0 



BjI. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VI, 




Injury by Boll Weevil to Squares. 

a Bloom checked bv attacks of larva: h. square opened, showing grown larva: c, square opened, 
showing pupa; d, dwarfed boll opened, showing one larva and two pupa: e, weevil escaping 
from square; /, emergence hole of adult in square. (Original.) 



Jul. 1 14, Bureau of Entomology, U. 5. Dept. of Agriculture. 



Plate VII. 




Injury by Boll Weevil to Bolls. 

o, Three larvce in boll; b. emergence hole in dry unopened boll: r, two larvae in boll: d, weevils 
puncturing boll, e, opened boll, with two locks injured by weevil; /, large bolls severely 
punctured. (Original.) 



SEASONAL HISTORY. 45 

Table X shows that the number of feeding punctures per square is 

determined by seasonal influences, us is also the average number of 
days before falling. A comparison of the average time from the 
date of the attack to the falling of the square shows that squares 
which are only fed on, fall, as a rule, somewhat more quickly than do 
squares which only contain larvae and have never been led upon. 
Flaring takes place more rapidly as the result of feeding injury by 
the adult than from oviposition and injury from the developing stage. 
While only one egg is generally laid in a square, it appears from Table 
X that two feeding punctures are usually made in a square. 

Bolls are quite largely fed upon after infestation has reached its 
height. Small and tender bolls are often thoroughly riddled by the 
numerous punctures and fall within a short time. (See PI. VII.) 
Larger bolls may receive many more punctures but do not fall. 
In bolls an abnormal woody growth sometimes takes the place of the 
punctured fiber, and a softening and decay of the seeds often accom- 
panies this change. One or more locks may be destroyed, while the 
remainder of the boll develops in perfect condition. 

SUSCEPTIBILITY OF VARIOUS COTTONS.' 

During 1903 and 1904 experiments were conducted at Victoria, 
Tex., to ascertain the relative susceptibility of several varieties of 
American Upland, Sea Island, Egyptian, and Cuban cottons. The 
observations at the laboratory were made by carefully examining 
the plants, looking into each square, and removing every weevil and 
infested square found. If there were any distasteful or resistant 
cotton among these ii would surely be found in this way, and if any 
variety were especially attractive to the weevils it would be equally 
apparent. Since infested squares were removed, the accident of 
association or proximity would not determine the location of the 
weevils found, but all might be considered as having come to the 
cotton with equal opportunities to make their choice of food, and 
accordingly their location has been considered as indicating such 
choice. The period of observation extended from June to November, 
except with the Cuban cotton, which was planted late and began to 
square during the latter part of August. For the purpose of this 
comparison both the several varieties and the various plats of the 
American cotton will be considered together, as no evidence of 
preference was found among them. 

In making a comparison of tin 1 results three elements must be con- 
sidered for each variety of cotton: First, the number of plants of each 
variety; second, the number of days during which each kind was 
under observation; third, the total number of weevils found on each 
class of cotton. The elements of numbers of plants and time under 
observation may be expressed by the product of those two factors 
forming a term which we may call "plant days." The total number 
of weevils found upon any class of cotton divided by the number of 
plant days will give the average number of weevils attracted by each 
plant for each day, and these numbers furnish a means of direct com- 
parison and show at a glance the average relative attractiveness of 

> The following discussion is extracted, but modified, from Bui. 51, Bureau of Entomology, pp. 61-64. 



46 



THE MEXICAN COTTON-BOLL WEEVIL. 



each class of cotton. The results of this series of experiments are 
tabulated below: 

Table XI. — Relative attractiveness of various cottons to the boll weevil. 





Num- 
ber of 
plants. 


Total. 


Average. 




Class of cotton. 


riant 
days. 


Wee- 
vils 
found. 


In- 
fested 
squares. 


Weevils 
per plant 
per day. 


Infested 

squares 
per wee- 
vil. 


Relative 
attrac- 
tiveness. 


1903. 


62 


4,920 


287 


3,507 


0. 058+ 


12.2+ 


1.0 








5 

8 
8 


120 
552 
808 


11 
64 

207 


136 
1,089 
2,013 


.092- 
.116- 

.256+ 


12.4- 
17.0+ 
9.7+ 


1.6+ 




2.0 




4.4+ 






Total of 3 non-American cottons. . 


21 


1,480 


282 


3,238 


.191- 


11.5- 


3.3- 


1904. 


60 
5 
4 


3,780 
315 
252 


346 
117 
102 




.0914 
.371 + 
.405- 




1.0 






4.0 






4.4+ 









An examination of Table XI shows that American Upland cotton 
is less subject to attack by the weevil than any of the others, and that 
Egyptian (Mit Afiji) is by far the most susceptible. The weevils 
gathered so thickly on the Egyptian cotton that the plants could not 
produce sufficient squares to keep ahead of the injury, and therefore 
the average number of squares for each weevil is only three-fourths 
as great with that variety as with the less-infested kinds, but the 
average injury to each square was greater than with any other. It 
is possible that the greater amount of nectar secreted by the Egyptian 
cotton plants is responsible for this increased attraction of the weevils. 

The results are still further sustained by observations upon larger 
areas of American and Eg}^ptian cotton under field conditions in three 
localities in Texas, no weevils being removed from either kind. At 
Victoria, Tex., on August 26, 1903, an examination showed that 96 
per cent of Egyptian squares were infested, while an average of 13 
fields of American showed 75.5 per cent. At Calvert, Tex., on Sep- 
tember 4, Egyptian showed 100 per cent infested, while the American 
varieties growing alongside showed 91 per cent. Similar results were 
found at San Antonio. Though growing in close proximity, the Egyp- 
tian produced no staple whatever, while the American gave better 
than an average yield in spite of the depredations of the weevil. 

At Victoria, in the experimental tract during 1904, three varieties of 
Egyptian cotton (Mit Afifi, Janovitch, and Ashmouni) were tested side 
by side with American varieties. The Egyptian varieties uniformly 
failed to make a pound of cotton, while the American varieties aver- 
aged 400 pounds per acre. 

In accordance with these observations, it appears that in developing 
a variety of cotton which shall be less susceptible to weevil attack, by 
far the most promising field for work lies among the American varie- 
ties, and of these the very early maturing kinds are most promising. 

The question of choice of different varieties for food was tested in 
the laboratory by Dr. A. W. Morrill, by placing squares of two kinds 
of cotton, American and Egyptian, in alternate rows in a rearing cage 



SEASONAL HISTORY. 



47 



so lettered and numbered that each square could be exactly located. 
Weevils were then placed so that they could take their choice of 
these squares, and observations from 8 a. m. to 6 p. m. were made 
upon the location and activity of the weevils. Though this experi- 
ment was repeated four times no positive evidence was obtained to 
show that weevils had any choice as to which kind of squares they 
fed upon. Table XII presents a summary of these results. 

Table XII. — Rearing-cage observations upon boll weevil choice of American and Egyptian 

squares. 







> 
9 




American squares. 


Egyptiai 


squares. 










ra 


b. 




u 

e 


8 


1 


Period of observation. 


ft c 

.2 


•a 

3 


E 

3 


•6 


3 


3 
o 

a 


E 

3 


•a 


3 
ft . 


H 

3 

o 

d 










C 




C = 


3 




a 


q g 


3 


9 




E 

3 


> 

a. 


"3 


03 


3 


ft 


"3 


C3 




ft 

be 


w 




A 


!> 


H 


< 


fe 


W 


H 


<j 


fe 


W 


1 




8 
5 


10 

1(1 


10 
10 


12 
5 


15 

19 


5 
1 


10 

16 


5 
5 


12 
13 


3 


2 


11.45 a. m. to 9.45 a. m 


3 


3 


12 in. to 5 p. m. day after 


5 


10 


10 


7 


25 


2 


10 


9 


27 


2 


4 


11.45 a. m. to 9 a. in 


5 
1 


10 
18 


16 
4 


6 
2 


17 
7 


6 



16 
4 


8 
2 


14 
10 


3 


5 









Total 






24 


58 


68 


32 


83 


14 


08 


29 


70 


11 









In experiments 1 and 2 the American squares were attacked more 
extensively than were the Egyptian, while in experiments 3 and 5 
greater injury was done to the Egyptian. In experiment 4 the smaller 
number of egg and feeding punctures made in the Egyptian squares is 
counterbalanced by the larger number of squares attacked. Although 
the totals from these five tests show slightly less injury to the Egyp- 
tian than to the American squares, it could hardly be expected that 
two arbitrarily chosen series, even if of the same variety, would show 
any closer agreement in the points of comparison made in this table 
than is therein shown by the American and Egyptian squares. 

Field examinations made in Cuba and Mexico on the native varie- 
ties of cotton showed them to be as susceptible to serious weevil 
injury as are the cultivated cottons. In some localities in Central 
America the dwarf character of the cotton grown, the very open 
method of cultivation, and certain protective adaptations on the part 
of the plants result in the production of fair crops, though the varieties 
of cotton grown are by no means immune to weevil attack. 



DURATION OF LIFE OF ADLILT WEEVILS. 



The subject of longevity is one which naturally divides itself into 
several headings. Many factors must be considered, among which 
are the nature of the food supply, seasonal conditions, the sex of the 
individual, and the time of entrance into and emergence from hiber- 
nation. 

The maximum record of longevity of any boll weevil is that of a 
hibernated weevil at Tallulah, La. (1910), which was fed squares 
after emergence and lived a total of over 335 days. The maximum 
recorded period of hibernation without food is 240 days, and the maxi- 
mum recorded length of life of hibernated weevils provided with food 



48 



THE MEXICAN COTTON-BOLL WEEVIL. 



after emergence is 130 days for males at Dallas, Tex. (1907), and 118 
days for females at Calvert, Tex. (1907). The maximum recorded 
length of life of hibernated weevils unfed after emergence is 90 days 
for males and 88 davs for females, both records being made at Dallas 
in 1907. 

A considerable number of records are available to illustrate the 
relative sustaining power of the various kinds of weevil food. (See 
Table XIII.) These records are especially valuable in making com- 
parisons with the sustaining power of other plants suspected of being 
possible food plants. It will be noticed that the same food has vary- 
ing sustaining power at different seasons. 

Table XIII. 

DURATION OF LIFE OF REARED BOLL WEEVILS WITHOUT NORMAL FOOD. 



Season. 



June-July . 

Do 

Do.... 



Total for reared weevils 
with grain. 



July. 
May. 
July. 
May. 
July. 



Do. 
Do. 



Total for reared weevils on 
weed leaves. 



June- July 

August-October . 



Total for reared weevils on 
water only. 



June 

August 

July 

June 

July 

Do 

June 

September 

September-November. 



Total for reared weevils on 
malvaceous buds. 



September 

October November — hibernation 

quarters offered. 



Sustenance provided. 



Hay.. 
Oats . . 
Corn.. 



Tie vine 

Hibiscus leaf... 

Sunflower 

Okra leal 

Pigweed 

Blood weed 

Bermuda grass . 



Water. 
....do. 



Jap. Hibiscus buds 

....do 

Callirrhoe buds 

Hibiscus alricanus buds... 

Hollyhock buds 

Hibiscus moscheutos buds. 

Okra buds 

Hibiscus milliards buds... 
....do 



Fresh sorghum cane. 



Num- 
ber of 
weevils 



Number 

of weevil 

days. 



47.7 
44.9 
34 



101 



339. 8 
306. 3 



25 

19 

235 

92 

IS 

36 

78 

305 

486 



1,294 



193 

020 



A ver- 
age lon- 
gevity. 



2.5 
2.9 
3.4 



3 

3 

3.2 

3.3 

3.4 

3.6 

3.8 



3.3 



4.3 
4.2 



2.0 
2.1 
5.6 

5.7 
6.0 
6.0 
7.8 
7.2 
27.0 



8.1 



11.3 
24.0 



Maxi- 
mum 
lon- 
gevity. 



10 

10 

' + 43 

43 



DURATION OF LIFE (AFTER EMERGENCE) OF HIBERNATED WEEVILS WITHOUT 

NORMAL FOOD. 



June-July 

Do 

Total for hibernated weevils 
without water. 
March-May 



Excelsior 
Rice 

Water... 



13 
14 


32.5 
45.2 


2.5 
3.2 


27 

5,701 


77.7 
59,021.8 


2.8 
10.3 



1 This weevil then entered hibernation and remained therein 126 days. 



SEASONAL HISTORY. 



49 



On sweetened water 12 weevils lived an average of a little less than 
6 days. Six weevils fed upon molasses alone lived an average of 11.5 
days. 

Without food or water 50 weevils, just developed but not fed, lived 
an average of 5 days; 15 which were 7 weeks old lived 6 days; and 
IS which were one month old lived 7.5 days. 

Table XIV. — Duration of life of boll weevils with normal food. 



July-September 

September-No veinber . 



Total for weevils fed on bolls 



February-July 

October- December . 



Total for weevils fed on foliage. 



April-June 

June-July 

August-September.. 

September-October . 
October-December. 



Total for weevils fed on squares. 



Sustenance provided. 



Bolls.. 

do. 



Foliage. 
do.. 



Squares. 

do.. 

do.. 

do.. 

do.. 



Num- 
ber of 
wee- 
vils. 



4,2(11 
92 



4,353 



170 
91 
64 
18 
10 



Number 
of weevil 

davs. 



684.5 

981.0 



103.931.1 
2. 950. 9 



106. 882. 



12, «9. I 
3,363.2 
4,796.0 

1.170.0 
359.0 



22, 127. 



Aver- 
age 
lon- 
gevity. 



18.5 
21.8 



20. 3 



24. 3 

32.0 



24.5 



7:;. l 
36.9 
74.9 
65.0 
3.5. 9 



62.: 



Maxi- 
mum 
lon- 
gevity. 



4-20 
69 



69 
130 



130 



105 

58 

135 

4-76 



135 



These records show the following longevity for weevils fed on 
different portions of the cotton plant: On bolls, 20.3 days; on foliage, 
24.5 days; on squares, 62.7 days. The sustaining power of foliage is 
therefore about 20 per cent higher than that of bolls, and that of 
squares 150 per cent higher than that of foliage. This indicates that 
the squares are by far the most suitable form of food. 

A number of observations were made on the relative longevity of 
weevils of different generations when fed upon cotton squares. 
Weevils of the first generation lived 57 days; of the third, 48.5 days, 
and of the fifth, 65 days. 

Newly reared weevils evidently have not the vitality of weevils 
emerged from a long hibernation, for they can not live so long on 
water alone. The boll weevil can find nourishment in several species 
of malvaceous plants which will sustain life twice as long as water 
alone, and in certain conditions as long as cotton foliage. It is inter- 
esting to note that the sweetened water from sorghum cane had 
almost three times the sustaining power of pure water. 

In connection with these studies figures were obtained upon the 
relative food value of the various foods to the two sexes. Trie data 
obtained may be tabulated as follows. 



28873°— S. Doc. 305, 62-2- 



50 THE MEXICAN COTTON-BOLL WEEVIL. 

Table XV. — Duration of life of boll weevils according to sex. 





Season. 


Food pro- 
vided. 


Males. 


Females. 


Condition. 


Num- 
ber. 


Weevil 
days. 


Lon- 
gevity. 


Num- 
ber. 


Weevil 
days. 


Lon- 
gevity. 






None 

Hay 

Oats 

Corn 

Rice 

Water 

...do 

Bolls 

Foliage 

Squares . . . 
...do 


7 

9 

7 

5 

8 

4 

2,638 

HI 

1,672 

90 

57 


13.3 

19.8 

18.9 

17.0 

27.2 

14.8 

27,052.5 

315.2 

42, 185. 7 

7,207.0 

3,198.0 


1.9 
2.2 
2.7 
3.4 
3.4 
3.7 
10.2 
19.7 
24.6 
80.0 
56.1 


6 
9 
8 
5 
6 
8 
1,980 
21 
1,337 
68 
44 


19.2 

27.9 

26.0 

17.4 

18.0 

30.8 

19,895.5 

319.2 

34,752.1 

4,752.0 

2,432.0 


3.2 




June-July 

do 


3.1 


Do 


3.25 


Do.. 


do 


3.4 






3.0 




do 


3.85 


Hibernated 


March-June 

July-September.. 

March-July 

do 


10.0 
15.2 


Hibernated 

Do 


25.9 
69.8 




July-October 


55.2 






Total 


4,513 


80,069.4 


17.7 


3,492 


64,290.1 


18.4 











Table XV in some respects bears out other findings as to the 
superior hardihood of the female sex. It will be noticed that the 
female's superior vitality is shown in all the cases where the food 
supply is abnormal. Nevertheless, it is noticeable that in the case 
of weevils fed on squares and bolls the males had the greater longevity. 



CANNIBALISM. 



It is hardly proper to speak of cannibalism as a food habit of the 
boll weevil, but the facts observed may well be recorded here. Under 
the impulse of extreme hunger weevils have several times showed a 
slight cannibalistic tendency. 

Seven beetles were confined in a pill box without food. On the 
third day six only were alive. Of the seventh only the hardest 
chitinized parts (head, proboscis, pronotum, legs, and elytra) 
remained, the softer parts having been eaten by the survivors. 

In another box containing 12 adults the leaf supplied for food was 
insufficient, and on the fourth day eight were dead, four were partly 
eaten, and others had lost one or more legs each. 

In another case a few young adults and a number of squares con- 
taining pupse were placed in a box together with a few fresh squares 
to serve as food for the adults. When the box was opened after a 
number of days one adult was found having its elytra eaten through 
and most of its abdomen devoured. In spite of this mutilation the 
victim was still alive and kicking slowly. The squares were still 
fresh and fit for food, so that this is really the clearest case of canni- 
balism observed. 

Frequently more than one larva hatches in a square, and when 
this is the case a struggle between them is almost certain to take 
place before they become full grown. Many cases have been 
observed in which squares contained one living and one or more 
smaller dead larvae, while in a few cases the actual death struggle 
was observed. 

i From Bulletin 51, Bureau of Entomology, p. 48. 



SEASONAL HISTORY. 



51 



SEASONAL PROPORTION OF SEXES. 

The most careful records of the sexes have been made in connec- 
tion with the hibernation period. The records are presented here- 
with in tabular form, grouping the specimens as hibernated weevils, 
reared weevils taken during the spring and summer, and autumn 
weevils which were about to hibernate: 

Table XVI. — Sex of hibernated boll weevils. 



Year. 



Locality. 



Male. 



Number. Percent 



Female. 



Number. Percent 



1902-03. 
1903-04. 
1903-04. 
1905-06. 
1905-06. 
1906-07. 
1906-07. 
1906-07. 



Total 

Weighted averages. 



Victoria, Tex. 
Calvert, Te.\ . . 
Victoria, Tex. 
Dallas, Tex . . . 
Victoria, Tex. 
Dallas. Tex... 
Calvert, Tex.. 
Victoria, Tex. 



269 

tn 

203 

173 

84 

1,668 

948 

l,0(i0 



5,045 



60.8 
59.7 
57.1 
57.7 
59. li 
54.1 
52.9 
61. 3 



174 
27 
153 
L27 

57 

1,412 

846 

1,049 



3,845 



39.2 
40.3 
42. 9 
42.3 
40.4 
45.9 
47.1 
38.7 



Table XVII. — Sex of spring and summer reared, boll weevils. 



Year. 



Locality. 



Male. 



Number. 



Percent. 



Female. 



Number. 



Percent. 



1902. 
1903. 
1906. 
1907. 
1910. 



Total 

Weighted average. 



Victoria, Tex. 

do 

Dallas, Tex... 
Overton, Tex. 
Tallulah, La.. 



240 
140 
63 



48.0 
53.1 
44.7 
47.4 
54.7 



927 



260 

124 

78 

10 

393 



52.0 

46.9 

55.3 

52. 

45.3 



48.3 



Table XVIII. — Sex of autumn boll weevils ready to enter hibernation. 



Year. 


Male. 


Female. 


Number. 


Per cent. 


Number. 


Per cent. 


1904 


557 
3] 
63 
173 
173 
19 
29 


63.7 
62.0 
57.7 
68.9 
57. 7 
57.6 
52.7 


317 
19 

127 
78 

127 
14 
26 




1904 


38.0 


1905 


1906 


31 1 


1906 


4° 3 


1906 




1906 


47 3 






Total 


1,045 




708 














60.0 




40 










Total and weighted average for all seasons 


7,017 


57.2 


5, 418 









52 THE MEXICAN COTTON-BOLL WEEVIL. 

From these determinations it appears that males are somewhat 
more numerous than females, the percentage based on our observa- 
tions being 57.2 males to 42.8 females. It is noticeable also that the 
males are in preponderance throughout the year. Since the males 
are less active in their movements than are the females, the advantage 
of the existence of the majority of males becomes apparent. The 
larger number of males and the more active habits of the females 
serve to increase the chances for the meeting of the sexes. 

It has been shown by rearing experiments conducted at low tem- 
peratures that the retardation of the development, such as is due to 
cold weather, favors the development of the males. 

FERTILIZATION. 

AGE AT BEGINNING OF COPULATION. 

After the adult weevils have left the squares a certain period of 
feeding is necessary before they arrive at full sexual maturity. 
This period varies in length according to the temperature prevailing 
and appears to bear about the same ratio to the developmental period 
as does the pupal stage. With weevils fed upon leaves alone the 
period preceding copulation is about twice the normal length, in the 
cases observed, of those having squares to feed upon. Mr. Cushman, in 
observations at Tallulah, La., in 1910, found that the period from emer- 
gence of the female to copulation varied from two to seven days, with 
an average of 4.4 days. During hot weather it is probable that this 
period averages three or four days, but as the weather becomes colder 
it increases gradually until the weevils may become adult, feed for 
a time, and go into hibernation without having mated. It should not 
be understood, however, that weevils do not usually copulate before 
hibernation. Mr. C. E. Hood made numerous observations of the 
exercise of this function in the fall of 1909 at Mansura, La. 

SEXUAL ATTRACTION AND DURATION OP COPULATION. 

The distance through which the attraction of the female insect will 
influence the male varies extremely. In observations made by Dr. 
Hinds at Victoria, Tex., it was found that the male was unable to 
recognize the female at a much greater distance than an inch. Obser- 
vations carried on in the field, as well as in the laboratory, tend to 
show that the sexes are attracted only when they meet, as they are 
likely to do either on the stems or upon the squares of the plant. 

In a considerable number of cases that were timed the average 
duration of the sexual act was very nearly 30 minutes. The earliest 
spring records of copulation available are for April 15. 

DURATION OF FERTILITY. 

A number of femaies which were known to have mated were isolated 
to determine the duration of fertility. Although the limit was not 
determined exactly, the results proved very striking. Several of the 
females laid over 225 eggs each, and nearly all of them proved fertile. 
Selecting three cases in which the facts are positively known, it 
appears that fertility lasted for an average of something over 66 days 



SEASONAL HISTORY. 53 

and that during this period these females deposited an average of 
nearly 200 eggs. The maximum limits may possibly be considerably 
higher. In fact, a single union seems to insure the fertility of as 
many eggs as the average female will lay, and its potency certainly 
lasts for a period fully equal to the average duration of life. It is 
probable, however, that there are many cases of repeated fertilization 
of females. 

PARTHENOGENESIS. 

Several series of experiments were conducted at Dallas, Tex., in 
August, 1906, to determine whether the boll weevil can reproduce 
parthenogenetically. Mr. K. A. Cushman kept 24 unfertilized 
females in confinement for 259 weevil days, and found that they 
deposited only 43 eggs, all being placed outside of the squares. No 
fertile eggs were laid. The rate of oviposition was one egg per female 
every six days. With a similar purpose Dr. Hinds isolated 40 indi- 
viduals as soon as they matured. 1 Each beetle was supplied daily 
with fresh, clean squares and careful watch was kept for eggs. The 
first point noticed was that no eggs were found till the weevils were 
about twice as old as females usually are when they deposit their first 
eggs. After they began to oviposit it was found that a very small 
proportion of the eggs were deposited in the usual maimer within 
sealed cavities in the squares, but nearly all of them had been left on 
the surface, usually near the opening of an empty egg puncture. 
This same habit was shown by a number of females, and so can not be 
ascribed to the possible physical weakness of the individuals tested. 
The number of eggs deposited was unusually small, and the few placed 
in sealed cavities failed to hatch. After somewhat more than a 
month had been passed in isolation a few pairs were mated to see if 
any change in the manner of oviposition would result. The very 
next eggs deposited by these fertilized females were placed in the 
squares and the cavities sealed up in the usual manner, showing that 
the infertile condition had been the cause of the abnormal manner of 
oviposition. 

OVIPOSITION. 

AGE AT BEGINNING OP OVIPOSITION. 

As has been shown, normal oviposition never takes place until 
after fertilization has been accomplished, but it usually begins soon 
afterwards. Observations upon the age at which the first eggs are 
deposited can be made more easily and more positively than those 
upon the age at which fertilization takes place. In a general way, 
therefore, the observations here given may be cited as also throwing 
light upon the time of beginning copulation. Table XIX is intro- 
duced to summarize the various observations which have been made 
upon the period preceding oviposition. It will be noticed that the 
range is from 4 to 14 days during the breeding season. Of course, 
the weevils which hibernate before ovipositing are not to be consid- 
ered as of this category. 

1 Bulletin 51, Bureau of Kntomology, pp. 91, 92. 



54 THE MEXICAN COTTON-BOLL WEEVIL. 

Table XIX. — Age of the boll weevil at beginning of oviposition . 



Date adult. 


Place. 


Date first egg. 


Number 
of fe- 
males. 


Number 
weevil 
days. 


Average 
age. 


June 8-14 1903 




June 16-19 

July 14-19 

Aug. 5-7 


27 
11 

16 
8 
9 
4 

10 


150.0 
66.0 
44.0 

106.0 
72.5 

116.0 
56.0 
73.0 


5.55 


July 8-11, 1910. 


Tallulah, La 


6.00 


July 29-31 1910 


do 


6.29 


Aug. 14-22, 1910 . 


...do 


Aug. 21-28 


6.66 


Sept. 4-9 1902 




Sept. 16-17 


9.06 


Sept. 10-20, 1910... 


Tallulah, La 


Sept. 18-Oct. 8 

Oct. 16 


12.89 


Oct 2 1902 




14.00 


Nov. 9-11, 1902 . 


do 


Nov. 16-19 


7.30 






June 16-Nov. 19 






92 


683.5 


7.40 









EXAMINATION OP SQUARES BEFORE OVIPOSITION. 

In the course of a great many observations upon oviposition it was 
found that females almost invariably examine a square carefully 
before they begin a puncture for egg deposition. This examination 
is conducted entirely by means of senses located in the antennae and 
not at all by sight. In fact, the sense of sight appears to be of com- 
paratively small use to this weevil. In regard to the actual time 
spent in the work of examination before beginning a puncture, over 
sixty observations are recorded. These show that the average time 
is over two minutes. This examination of squares is made by females 
only when they intend to oviposit. Males have never been observed 
acting in this way, nor do females generally do so when their only 
object is to feed. 

SELECTION OF UNINFESTED SQUARES FOR OVIPOSITION. 

The sense by which the weevil examines the squares frequently 
enables it to detect an infested condition when no external sign is 
visible. Females sometimes refrain from placing eggs in squares, 
even when they are apparently searching for a place to oviposit and 
anxious to do so. The acuteness and accuracy of the preliminary 
examination is well shown by the fact that when provided with more 
squares than they have eggs to deposit they do not often place more 
than one egg in a square. Where a totally infested condition is 
reached, as is frequently the case in the field, no choice between in- 
fested and uninfested squares could be exercised, and then, unless the 
female happens to be in a condition to refrain from oviposition, she is 
forced to deposit more than one egg in a square. Table XX illus- 
trates the distribution of egg and feeding puncture as collated from 
many records. 

Table XX. — Selection of squares and relation of feeding to oviposition of the boll weevil. 



Place and time of 


Total 

squares 
attacked. 


Squares with 
1 egg each. 


Squares with 

more than 1 

egg each. 


Squares with 
both egg and 
feeding punc- 
tures. 


Squares fed on 
only. 




Num- 
ber. 


Per cent 
of total 
squares. 


Num- 
ber. 


Per cent 
of total 
squares. 


Num- 
ber. 


Per cent 
of total 
squares. 


Num- 
ber. 


Per cent 
of total 
squares. 


In laboratory, 1902.. . 
In field, 1902 


630 

151 

560 

1,036 

2,679 


477 
56 
317 
531 
413 


75.7 
37.0 
55.9 
51.2 
15.4 


19 

33 

83 

415 




3.0 
21.8 
14.8 
40.0 

0.0 


24 
46 
50 
90 
1,832 


3.8 
30.4 
8.9 
8.6 
68.4 


110 
16 

110 


434 


17.4 
10.5 


In field, 1903 


19.6 


In field, 1905 


0.0 


In field, 1907 


16.2 






Total 


5,056 


1,794 




550 




2,042 




670 






35.4 


10.8 


40.3 


13.2 











SEASONAL HISTORY. 55 

The observations show that 86.7 per cent of all squares attacked 
received eggs. It may also be seen that 40.9 per cent of all squares 
oviposited in received only one egg each. The squares which were 
only fed upon formed but 13.2 per cent of the total number attacked, 
and, as has been shown above, those receiving both egg and feeding 
punctures constituted 40.3 per cent. As the weevil injury overtakes 
the production of squares the proportion of squares containing both 
egg and feeding punctures increases rapidly. Where several eggs are 
placed in a square it is rarely the case that more than one larva 
develops. 1 If two or more hatch in a square one is likely to destroy 
the others when their feeding brings them together. Should eggs be 

E laced in squares which already contain a partly grown larva, those 
atching would probably find the quality of the food so poor that they 
would soon die without having made much growth. Since one egg 
will insure the destruction of the square and a number of eggs would 
do no more, it is plain that the possible number of offspring of a single 
female is increased directly in proportion to the number of her eggs 
that she places one in a square. Favorable food conditions for the 
larva are likewise best maintained by the avoidance of feeding upon 
squares in which eggs have been deposited and also by refraining from 
ovipositing in squares which have been much fed upon. Selection of 
uninfested squares is, therefore, of the greatest importance in the 
reproduction of the weevil, since this insures the most favorable con- 
ditions for the maturity of the largest possible number of offspring. 
Feeding and oviposition are common in the same boll, but unless 
the infestation is very heavy it appears that only rarely is more than 
one egg placed in one lock, though several are often deposited in the 
same boll. The number deposited depends considerably upon the 
size of the boll. The smallest, winch have just set, receive but one, 
as do the squares, and these fall and produce the adult weevil at about 
the same period as in the case of squares. Bolls which are larger 
when they become infested have often been found to be thickly punc- 
tured and to contain 6 or 8, and in one case 15, larvae. (See PI. VI, d; 
PI. VII, c.) 

DEPENDENCE OF REPRODUCTION UPON FOOD OBTAINED FROM SQUARES. 2 

During the fall of 1902 a series of experiments, lasting for 12 weeks, 
was made to determine the length of life of weevils fed solely upon 
leaves. In one lot, consisting of nine males and eight females, the 
average length of life of the females was 25 days, while that of the 
males was 36 days. Though this period far exceeded the normal 
time usually passed between the emergence of adults and the begin- 
ning of egg deposition, no eggs were found. Dissection of the females 
which lived longest showed that their ovaries were still in latent 
condition, though the weevils were then 81 days old. Few instances 
of copulation were observed among weevils fed upon leaves alone, 
and among nearly 70 weevils which were thus tested no eggs were 
ever deposited. After a period of three weeks upon leaves, 11 weevils 
were transferred to squares. Females in this lot began to lay in 
four days, and four of them deposited 323 eggs in an average time 

1 In one case four normal pupae were found in a single square. This observation was made at Shreveport, 
La by Mr. H. Pinkus. 
* From Hull. 51, Bureau of Entomology, pp. 112, 113. 



5G THE MEXICAN COTTON-BOLL WEEVIL. 

of 20 days. The conclusion seems plain that so long as leaves alone 
are fed upon, eggs do not develop, while a diet of squares leads to 
the development of eggs in about four days. It is worthy of note 
that the interval between the first feeding upon squares and the depo- 
sition of the first eggs is almost the same with these weevils taken in 
middle life as with weevils which have just emerged. 

An examination of hibernated females taken in the spring of 1903, 
which had fed for six weeks upon cotton leaves, showed that their 
ovaries were still latent. Copulation was rarely observed among 
hibernated weevils until after squares had been given them. In a 
few days after feeding upon squares, mating and oviposition began. 
The average period was from three to five days, and, having once 
begun, oviposition continued regularly. 

It has been found that food passes the alimentary canal in less than 
24 hours. Assimilation therefore must be very rapid. It is evident 
that while leaves will sustain life certain nutritive elements found 
only in squares are essential in the production of eggs. 

These experiments were repeated in 1904 with similar results. 

Upon dissecting weevils just taken from hibernation, it was found 
that females contained no developed eggs, but that their ovaries were 
in an inactive condition, similar to those of females which had fed for 
months entirely upon leaves during the previous fall. Upon examin- 
ing females taken from stubble cotton later in the spring, but before 
squares nad appeared, it was found that they also were in similar 
condition. This was also true of females kept in the laboratory from 
the time of emergence from hibernation until squares became abun- 
dant, with only leaves for food. It seems peculiar that upon a purely 
leaf diet eggs are not developed, but all observations made indicate 
that this is the case. It can not be said definitely whether the females 
examined had been fertilized, but it is certain that they were not 
ready to deposit eggs. 

PLACE OP EGG DEPOSITION. 

The location of egg punctures, while variable, still shows some 
selection on the part of the weevil. This may be due partly to the 
form of the squares and partly also to the size of the weevil, but what- 
ever the explanation, the fact remains that in a majority of cases the 
egg puncture is made on a line about halfway between the base and 
the tip of the square. When so placed the egg rests either just inside 
the base of a petal or among the lowest anthers in the square, accord- 
ing to the varying thickness of the floral coverings at that point. 
Punctures are very rarely made below this line, though they are some- 
times made nearer the tip. Almost invariably the egg puncture is 
started through the calyx in preference to the more tender portion 
of the square, where the corolla only would need to be punctured. 
With bolls no selection of any particular location has been found, 
but eggs seem to be placed in almost any portion. 

THE ACT OP OVIPOSITION. 

While engaged in making egg punctures, the favorite position of 
the weevil is with its bodyparallel to the long axis of the square and its 
head toward the base. The tip of the weevil's body is thus brought 
near the apex of a medium-sized square. It may be that the position 



SEASONAL HISTORY. 57 

described is especially favorable for obtaining a firm and even hold 
and this may nave something to do with the regularity with which 

it is assumed. Having selected her location, the female takes a firm 
hold upon the sides of the square and completes her puncture while 
in this position. 

The female begins drilling a hole by removing with the mandibles a 
little flake of the outer epidermis. Then, with her feet strongly braced 
by gnawing and pushing with an auger-like motion, she thrusts her 
beak into the tender portion of the square. At the bottom of the 
puncture she makes a small cavity by gnawing, at the same time 
moving about the hole with the beak as a pivot. Withdrawing her 
beak, she turns about with the center of her body as a pivot. This 
places the tip of her abdomen directly over the puncture, into which 
she thrusts her ovipositor. The ovipositor is protruded to the bot- 
tom of the cavity in which it appears to be firmly held in position by 
the two terminal papilla? and the enlarged terminal portion. Slight 
contractions of the abdomen occur while this insertion is being made. 
In a few moments much stronger contractions may be seen, and often 
a firmer hold is taken with the hind legs as the egg is passed from the 
body, and its movement may be seen as it is forced along within the 
ovipositor and down into the puncture. Only a few seconds are 
required to complete the deposition after the egg enters the opening 
to the cavity. Having placed the egg, the ovipositor is withdrawn, 
and just as the tip of it leaves the cavity a quantity of mucilaginous 
material, usually mixed with some solid excrement, is forced into the 
opening and smeared around by means of the tip of the abdomen. 
This seals the egg puncture, and the act of oviposition becomes 
complete. Sometimes the weevil fails to locate the puncture imme- 
diately with her ovipositor. In this event she searches excitedly, 
moving the tip of the abdomen about feeling carefully over the sur- 
face of the square. In this search, however, she never moves her 
front feet, apparently using the position of these as a guide to the 
distance through which she should search. Failing to locate the 
puncture in this way she again turns around and searches for it with 
her beak and antenna?. When the cavity has been found again the 
female invariably enlarges it before turning again to insert the ovi- 
positor. If the search with the antenna? does not prove successful, 
the female generally makes another puncture in the same manner as 
at first. 

The usual habit of the female in puncturing through the calyx 
enables it to seal the wound more thoroughly because of the healing 
power possessed by the calyx tissue. Punctures made in the corolla 
must remain open or are closed only by the slight filling of mucilagi- 
nous excrement by the weevil. Punctures through the cabyx will, in 
most cases, be healed by the natural outgrowth of the tissue so as 
completely to fill the wounds in a manner analogous to the healing 
of wounds in the bark of a tree. The custom of the weevil in sealing 
up its egg punctures with a mixture of mucous substance and excre- 
ment is of great advantage and assistance to the plant in the healing 
process. While undoubtedly applied primarily as a protection to the 
egg, it serves to keep the punctured tissues from diving and decay, 
and thus promotes the process of repair. As a result of the growth 
thus stimulated in the calyx, the wound is healed perfectly in a short 



58 THE MEXICAN COTTON-BOLL WEEVIL. 

time, and a corky outgrowth appears above the general surface pJane. 
This prominence has been termed a "wart." The healing is com- 
pleted even before the hatching of the egg takes place, and thus both 
egg and larva partake of the benefit of its production. Occasionally 
warts develop from feeding punctures, which were small, but the exact 
conditions under which this takes place have not been determined. 
Nevertheless, the presence of warts is the most certain external indi- 
cation of oviposition in squares. In a series of observations they were 
found to follow oviposition in 84 per cent of the cases. 

TIME REQUIRED TO DEPOSIT AN EGG. 

Careful observations have been made upon the time of egg deposi- 
tion. As in all other processes of the life history of this insect, the 
period of egg deposition is influenced by climatic conditions. It was 
found at Tallulah, La., in the early part of the summer of 1910, that 
the time required for making the puncture varied from 1 minute and 
20 seconds to 8 minutes and 27 seconds, with an average of 3 minutes 
and 36 seconds. On the other hand, at Victoria, Tex., in October, the 
average time was 5^ minutes, and the range from 1 to 13 minutes. At 
Tallulah the period for the deposition of the egg and the sealing of the 
puncture varied from 2 minutes and 45 seconds to 9 minutes and 30 
seconds, with an average of 4 minutes and 41 seconds. At Victoria 
the period ranged from 3 to 16 minutes and averaged 1\ minutes. 

STIMULATING EFFECT OF ABUNDANCE OF SQUARES UPON EGG DEPOSITION. 1 

Four actively laying females were confined together upon a few 
squares from September 22 to October 14, 1902. During this period 
they laid a total of 227 eggs, or an average of 2.37 eggs per weevil per 
day. For the next 13 days these same weevils were isolated and 
supplied with an abundance of squares. During this shorter period 
they laid 236 eggs, or 4.54 eggs per female daily. 

These figures are the more striking, because the stimulation was 
plainly shown in spite of the general tendency to lay fewer eggs as the 
weevils grow older and as the average temperature becomes lower. 

ACTIVITY OF WEEVILS IN DIFFERENT PARTS OF THE DAY. 

Two series of observations have been carried on to determine the 
hourly activity of the weevils. The experiments at Victoria were 
conducted in the early part of September, when the temperature 
was ranging from a little under 70° F. to 95° F. during the day. It 
was found that there was almost a perfect coincidence between the 
temperature curve and the curve of the average activity of the 
females in ovipositing. This is shown hi the accompanying diagram 
(fig. 5). 

It also appeared that the activity of the weevils began and ceased 
at about 75° F. Perhaps this indicates that the act of oviposition 
requires a zero of effective temperature different from that of develop- 
ment. This would be entirely analogous to conditions in flowers, 
where it is found that the various functions of the plant are governed 

» Modified from Bulletin 51, Bureau of Entomology, pp. 87, 88. 



SEASONAL HISTORY. 



59 



by independent laws of effective temperature. It appears also that 
the activity is much less on cloudy days than on clear days. At 
Tallulah, La., in 1910, observations were made on the periodic 
division of daily oviposition. The results are shown in Table XXI. 



FAHREN 
HEIT 


TIME 


I2p Um 2 3 4 5 6 7 8 9 10 II 12m Ipm 2 3 4 5 6 7 8 9 10 II 12 P 


100° 
95° 
90° 
85° 
80° 
75° 
70° 
65° 
60° 
















































































r^ 


ptt 












































& 


'£? 






v' 


^ 






































4 














<** 






























i 


•**/ 


/ / 

/ 














\ 


^ 


?- 


























A 


^ 


/ 




















«* 


















77>t 




u 


P 




\ 


Ow 


'ra 


?e C 


let 


\tti\yoffvi4 d 


fen, alt' w>ev 


lis 






























on ieplember 


3.t&S,/.?02 













































































































Fig. 5.— Diagram showing average activity of Ave female boll weevils. (After Hunter and Uinds.) 

Table XXI. — Summary of periodic division of oviposition, based upon nine boll weevils, 

Tallulah, La., July, 1910} 



Period. 


Total eggs 
laid. 


Average 

number of 

eggs per 

hour. 


Per cent 
of total 
oviposition 
in* each 
period. 


Average 

eggs per 

weevil 

per hour. 




25 
10 
21 
17 
35 


5.00 
.59 
2.10 
2.13 
4.38 


23.15 
9.26 
19.44 
15. 71 
32.41 


0.63 




.07 




.26 




.27 




.55 







From these records it may be seen that the warmest part of the 
day is the most active period for the weevils. 



SEASONAL RATE OF OVIPOSITION. 



Since the period of reproductive activity of the boll weevil is so 
long, the rate at which eggs are deposited is a question requiring 
much time for its determination. The rate of oviposition is at least 
as strongly influenced by variations in temperature as is the rate of 
development, and it is very probable that some of the previously 
unaccountable and abrupt variations in the rate upon succeeding 
days may be explained by the relative humidity or by the amount of 
sunshine. The rate is influenced also by the abundance of clean 
squares which the weevil can find, so that it is greater in the early 

Eart of the season as the degree of infestation is approaching its 
mit than after infestation has reached its maximum. Several 
series of observations have been made upon the rate of egg deposi- 
tion. These have been tabulated below in Table XXII. 



1 From Cushman, Journ. Econ. Ent., vol. 4, p. 436. 



60 THE MEXICAN COTTON-BOLL WEEVIL. 

Table XXII. — Seasonal rate of oviposition of the boll weevil. 



Place. 


Time. 


Num- 
ber of 
females. 


Num- 
ber of 
weevil 
days. 


Aver- 
age 
period 
of ovi- 
posi- 
tion. 


Total 
number 
of eggs. 


Aver- 
age 
num ber 
of eggs 
daily. 


Aver- 
age 
total 

number 
per 

female. 


Maxi- 
mum 
number 
in one 
day. 




Aug.-Dec.,1902... 
Sept.-Oct.,1902... 

do 


3 1 
40 

4 

9 

3 51 

3 24 
3 
4 
2 
3 
39 
34 


135 

247 

( 23 

\ 13 

352 

2.018 

1,395 

21 

12 

23 

108 

310 

183 


135 

G 

} • 

39 
39 
58 
7 
3 
11 
36 
34 
45 


255 

1,248 

/ 227 

\ 230 

990 

5,254 

3,541 

112 

55 

81 

233 

1,830 

887 


1.88 
5.05 
2.37 
4.54 
2.81 
2.60 
2.53 
5.32 
4.56 
3.68 
2.15 
5.90 
4.85 


255.0 
31.2 

| 116.0 

110.0 
103.0 
147.5 
37.3 
13.7 
40.5 
77.6 
203. 3 
221.7 




Do 




Do 




Do 


Oct.-Dec.,1902.... 
May-July, 1903.... 
June-Sept., 1903... 
Aug., 1904 




Do.' 

Do. 2 


18 


Do 




Terrell, Tex 


Sept., 1904 

July-Aug.,1905... 
Aug.-Sept.,1905... 
June- Aug., 1910... 
Aug.-Oet.,1910... 




Dallas, Tex 


8 


Do 


20 


Tallulah.La.i. . 


20 


Do. 2 ... 


12 






Total 


154 


4,840 




14,949 






20 












Average 






31 




3.13 


97.07 















1 Hibernated weevils. 

2 First generation weevils. 

3 Observed for entire oviposition period and used in discussion of fecundity. 

The influence of temperature upon the rate of oviposition may be 
shown by the following diagram (fig. 6), wliich expresses in a single 
line the mean number of eggs laid daily at a 
given temperature. There is, of course, more 
or less fluctuation from the mean, and it is 
due mostly to differences in humidity. 

The maximum number of eggs deposited by 
any weevil in one day has been recorded by 
Mr. Cushman as 20 at Tallulah, La. At Vic- 
toria, Tex., Dr. Morrill recorded two weevils 
to have laid 108 eggs in three days, or at the 
rate of 18 eggs per day. Dr. Morrill found 
that the size of weevils did not affect the rate 
per day, as four very small females laid 761 
eggs at the rate of 3.3 eggs per day. It will 
be noticed that this rate is higher than the 
average of all the records in Table XXII. The 
number of eggs produced on the first day of 
oviposition varies from one to seven. About 
67 per cent of the weevils at Victoria were 
found to oviposit fewer than three eggs on the 
first day. 



90 
V 


A/of-tB£/f Of£G6S 

' 2 3 4 S 6 
















i? 






























I 
* 






























W 

















Fig. 6. — Diagram to illustrate 
influence of temperature 
on average rate of oviposi- 
tion of boll weevil. (Orig- 
inal.) 



IS THE FECUNDITY OP THE WEEVIL DECREASING? 

In view of the fact that recent observations have shown a decrease 
in the fecundity of the gipsy moth in Massachusetts, 1 we have 
selected from the foregoing table (Table XXII) on the seasonal rate 
of oviposition the rather meager data bearing on the question of 
whether the fecundity of the boll weevil is decreasing. We find 76 



■ Howard and Flske, Hull. 91, Bur. Ent,, U. S. Dept. Agr., pp. 109, no, 1911. 



SEASONAL HISTORY. 61 

weevils at Victoria, Tex., in 1902 and 1903, laying an average of 119 
eggs in an average period of 46 days, and at the rate of 2.6 eggs 
per day, with a maximum of 18 eggs in one day; while at Tallulah, 
La., in 1910, 13 weevils laid an average of 209 eggs in an average 
period of 37 days and at the rate of 5.7 eggs per day, with a maxi- 
mum of 20 eggs in one day. While these facts appear to indicate 
that the fecundity of the weevil is not decreasing, they do not, on 
the other hand, because of the great difference in the places of 
observations, prove an increase. More detailed data will be obtained 
on this point in the future. 

PERIOD OF OVIPOSITION. 

With the exception of hibernated weevils it appears that ovipo- 
sition begins with the majority of females in about seven days after 
they emerge as adults to feed and continues uninterruptedly until 
shortly before death. In the case of 43 weevils observed at Tallulah, 
La., in 1910, the average preoviposition period was 7.72 days, the 
minimum 5, and the maximum 23 days. While females fre- 
quently deposit their last eggs during the last day of their life, a 
period of a few days usually intervenes between the cessation of 
oviposition and death. 

The known maximum number of eggs laid by a single individual 
is 304. This was in the case of a weevil which lived for 275 days 
and deposited eggs at the rate of 7.6 eggs per day for 41 days. The 
maximum period of oviposition recorded is 135 days. In the case 
of 52 hibernated weevils at Victoria the period of oviposition averaged 
about 48 days, the maximum being fully 92 days. In an average 
rate with 21 females in the first generation the actual period was 
almost 75 days, the maximum being 113 days. The average period 
for the females of the first two generations appears to be longer than 
that for any other. In the third generation the average period for 
11 females was 58 days, the maximum being 99 days, and in the 
fifth generation for 5 females the period averaged 48 days, with the 
maximum only 62 days. At Tallulah, La., m 1910, the average 
oviposition period was found to be 34.44 days. The average period 
for all of the records available is but 31 days. 

The approach of cold weather cuts short the activity of the weevils 
which become adult after the middle of August, thereby decreasing 
the length of their oviposition period. Weevils which pass through 
the winter usually live longest, but as it requires more or less vitality 
to pass through the long hibernation period, their activity in the 
spring is thereby lessened. 

EFFECTS OF OVIPOSITION UPON SQUARES. 

As has been explained elsewhere, the attack of the weevil on the 
square causes it to form an absciss layer, which ultimately causes it 
to separate entirely from the plant. One of the immediate effects of 
attack is the flaring of the square, that is, the spreading of the bracts 
and their subsequent yellowing and drying. (See PI. I.) Flaring 
may result from many other causes besides boll-weevil injury. When 
resulting from weevil injury it does not begin, as a rule, immediately 
after the injury, but only within from one to three days of the time 



62 THE MEXICAN COTTON-BOLL WEEVIL. 

when the square will be ready to fall. In especially severe cases of 
feeding injury flaring often results in less than 24 hours. Occasionally 
the growth of the square overcomes the injury from feeding, and the 
bracts, after having flared, again close up and the square continues 
its normal development and forms a perfect boll. When injured by 
the feeding of a young larva as the direct result of successful oviposi- 
tion, flaring was found in 193 cases to take place in an average of 
7 days from the deposition of the egg. (See Pis. V, VI.) 

After an average period of 2.5 days subsequent to flaring the 
square was found to fall to the ground, although it may sometimes 
hang by a thread of the bark. The average time from egg deposi- 
tion to the falling of the square in 539 cases from June to September 
was found to be about 9.6 days, which is about the middle point of 
the weevil development. It has been shown in another place (Table 
XXVII) that the period before the falling of the square has a direct 
bearing upon the period of the development of the weevil. 

PROBABLE ORIGINAL BREEDING HABIT. 

There is nothing to indicate that the boll weevil has changed its 
food plant, although it may have done so. It is now confined, as far 
as we know, to the various species and varieties of the genus Gossy- 
pium. The boll weevil belongs to a genus of weevils every species of 
which is confined in its food habits to a single species or genus of food 
plants. The majority of the species of Anthonomus and perhaps all 
that belong to the true genus normally breed in buds. It is therefore 
reasonable to assume that the normal habit of the boll weevil is to 
breed in the cotton buds or "squares," and that its habit of breeding 
in the bolls is an adaptation due to the necessity of providing for the 
great number of weevils which develop in the later part of the season. 
A study of the length of the development of many species of Antho- 
nomus leads the authors to believe that the short developmental 
period in squares is perfectly normal and that the longer period in 
Dolls is due merely to environmental conditions, as is explained under 
the subject of development. 

THE EGG. 
DURATION OF EGG STAGE. 

Concealed as the eggs are beneath several layers of vegetable 
tissue, it is impossible to examine them to ascertain the exact length 
of the egg stage without in some degree interfering with the natural- 
ness of their surroundings. The beginning of the stage is easily 
obtained by confining female weevils with uninfested squares. By 
making a large series of observations about the time that the larvse 
should hatch it is possible to obtain the average length of the egg 
stage. The extreme range which has been observed in the duration 
of this stage is from 1 to 17 days, while the average period for the 
whole number of observations is but 3.7 days. It is possible that the 
embryo can undergo an even greater retardation without losing its 
vitality. The period of embryonic development is lengthened by 
decreases in the temperature and also by lowered atmospheric 
humidity. Thus it was found that between 79° F. and 81° F. the 



SEASONAL HISTORY. 



63 



egg stage averaged 1.9 days at Alexandria, La., 2.61 days at Tallulah, 
La., 3.73 days at Victoria, Tex., and 4.1 days at Dallas, these differ- 
ences corresponding quite regularly to the differences in the humidity 
of the various places. Table XXIII is presented to show the data 




Fig. 7.— Diagram illustrating relationship of temperature to the egg period of the boll weevil at Victoria, 

Tex., in 1902. (Original.) 

which have been obtained on this stage, and is accompanied by two 
diagrams (figs. 7 and 8) to illustrate the relationship between mean 
temperature and the length of the egg period. 

Table XXIII. — Duration of the egg stage of the boll weevil. 



Place. 



Victoria, Tex... 

Do 

Do 

Do 

Do 

Do 

Alexandria, La. 
Dallas, Tex 

Do 

Tallulah, La.... 



Total 

Average 



Year. 



1902 
1902 
1902 
1902 
1902 
1903 
1907 
1908 
1908 
1910 



Eggs laid. 



Sept. 4-29 

Oct. 7-20 

Nov. 7 

Nov. 24-28 

Dec. 2-9 

May 27-June 5 . 
Aug. 31-Sept. 5. 

July 17-20 

Aug. 14 

June27-July 10. 



Eggs hatched. 



Sept. 7-Oct. 3 . 

Oct. 11-24 

Nov. 13 

Dec. 5-15 

Dec. 15-18 

Mav30-June9. 

Sept. 2-7 

July 20-23 

Aug. 17 

July 1-12 



Num- 
ber of 
eggs 
laid. 



3S4 
95 
12 
17 
19 
25 

229 
35 
11 
44 



Total 
num- 
ber of 
egg 
days. 



1,434 
430 

72 
214 
264 

93 
436 
145 

33 
115 



3,236 



Aver- 
age 
period. 



Days. 
3.73 
4.52 
6.0 
12.59 
13.9 
3.75 
1.9 
4.1 
3.0 
2.61 



3.7 



Mean 
temper- 
ature. 



F. 

81.0 

73.0 



62.0 



72.5 
79.2 
81.6 
88.0 



64 



THE MEXICAN COTTON-BOLL WEEVIL. 



Ds4YS 
5 /O /S 



HATCHING. 

Wliile still within the egg the larva can be seen to work its man- 
dibles vigorously, and although a larva has never been seen in the act 
of making the rupture which allows it to escape from the egg, it is 
believed that the rupture is first started by the mandibles. The 
larvae do not seem to eat the membranes from which they have 

escaped, but owing to the extreme delicacy 
of the skin it is almost impossible to find 
any trace of it after the larva has left it 
and begun feeding on the square, the mem- 
branes having been found in only a few 
cases. 

HATCHING OF EGGS LAID OUTSIDE OF 
COTTON FRUIT. 

It occasionally happens that a female is 
unable to force an egg into the puncture 
prepared to receive it, and the egg is laid 
on the outside of the square or boll. Eggs 
so placed usually shrivel and dry up within 
a short time. To test the possibility of a 
larva making its way into the square from 
the outside a number were protected from 
drying. Of the 19 eggs tested, 6 hatched 
in from two to three days. In no case, 
however, was the young larva able to make its way into the square, 
and it soon perished. The hatching of eggs laid outside, therefore, 
appears to be of no importance, since the larva? must perish without 
doing any damage. 

On August 23, 1906, Mr. R. A. Cushman observed the hatching 
of two larvae under water from eggs which had been submerged over 
24 hours. 




Fig. 8. — Diagram illustrating relation- 
ship of temperature to the egg pe- 
riod of the boll weevil and showing 
variations due to humidity. (Orig- 
inal.) 



EATING OF EGGS DEPOSITED OUTSIDE. 



The number of eggs left outside increases as the female becomes 
weakened and is especially noticeable shortly before her death. 
Repeated observations have shown that unfertilized females generally 
deposit their eggs on the outside, and only occasionally is an infertile 
egg deposited normally, though the attempt is regularly made to do 
so. The number of such eggs which may be found is greatly decreased 
by a peculiar habit observed many times, which will be described. 
Occasionally it appeared that the puncture which the female had 
made for the reception of an egg was too narrow to receive it, and 
after a prolonged attempt to force it down the female, would with- 
draw her ovipositor, leaving the egg at the surface. She would then 
turn immediately and devour the egg. In some cases more than one 
has been devoured after repeated failures to place them properly in 
the squares. 



SEASONAL HISTORY. 65 

PERCENTAGE OF EGGS THAT HATCH. 

Definite records have not been kept regarding the percentage of 
eggs that hatch, but in the many hundreds of eggs followed during 
these observations very few have failed to hatch. Though some are 
much slower in embryonic development than are others laid at the same 
time and by the same female, it is probable that less than 1 per cent 
of the eggs are infertile or fail to hatch. It must be considered, 
however, that proliferation crushes many eggs. This proliferation 
is most aggressive against the eggs in the bolls in the late fall. 

THE LARVA. 
FOOD HABITS. 1 

It is plainly the instinct of the mother weevil to deposit her egg so 
that the larva upon hatching will find itself surrounded by an abun- 
dance of favorable food. In the great majority of cases this food 
consists principally of immature pollen. This is the first food of the 
larva which develops in a square, and it must be both soft and 
nutritious. Often a larva will eat its way entirely around the inside 
of a square in its pursuit of this food. In most cases the larva is 
about half grown before it feeds to any extent upon the other por- 
tions of the square. It may then take the pistil and the central 
portion of the ovary, scooping out a smoothly rounded cavity for the 
accommodation of its rapidly increasing bulk. So rapidly does the 
larva feed and grow that in rather less than a week it has devoured 
two or three times the bulk of its own body when fully grown. It 
sometimes happens that the square is large when the egg is depos- 
ited therein, and the bloom begins to open before the injury done 
by the larva becomes sufficient to arrest its development. In many 
cases of this kind the larva works its way up into the corolla and 
falls with it when it is shed, leaving the young boll quite untouched. 
Occasionally the flower opens and fertilization is accomplished before 
any injury is done the pistil, and in rare cases a perfect boll results 
from an infested square. Sometimes the larva when small works its 
way down into the ovary before the bloom falls, and hi such cases 
the small boll falls as would a square. (See PI. VI, a, b, d.) 

In large bolls the larvae feed principally upon the seed and to 
some extent upon the immature fiber. A larva will usually destroy 
only one lock in a boll, though two are sometimes injured. When 
the infestation is severe a number of weevils, occasionally as many 
as six or even more, may be developed in a single boll, which is 
completely destroyed by the feeding of the larvae. (See PI. VII, a, c.) 

GROWTH. 

The rate of growth, of course, is dependent upon many external 
conditions. It has been found that in squares during the hot weather, 
the length of the body increases quite regularly by about 1 mm. a day. 
Full grown larva? vary in length from 5 to 10 mm. across the tips of 
the curve. Larva? of normal size in squares average from 6 to 7 mm. 
The largest larva 1 are developed in bolls which grow to maturity. 

1 From Bulletin 51, Bureau of Entomology, p. 49. 

28873°— S. Doc. 305, 62-2 5 



66 



THE MEXICAN COTTON-BOLL WEEVIL. 



MOLTS. 



/S 2Q 



To accommodate the rapid growth of the larvae two or three molts 
occur. The first occurs at about the second day, and the second at 
about the fourth day. Whether a third molt occurs before pupation 
can not be positively stated, but having occasionally found larva? which 
had certainly just molted, but which were not larger than the usual 
size of the second molt, we are led to suspect that three larval molts 
may sometimes occur, though possibly not always. In bolls where 

the length of the larval stage is 
often three or four times as great as 
that usually passed in squares, it 
seems almost certain that more than 
two larval molts occur regularly. 
According to Dr. Hinds's obser- 
vations the skin splits along the 
back, starting at the neck, and is 
then pushed downward and back- 
ward along the venter of the larva. 
The cast head shield remains at- 
tached to the rest of the skin. 

DURATION OF LARVAL STAGE. 

The length of the larval stage, as 
a rule, is about equal to the sum 
of that of the egg and pupal stages. 
It lengthens as the temperature 
falls and also as the amount of mois- 
ture decreases. It is also probably 
influenced by the nature and con- 
dition of the food supply. These influences will be discussed more 
fully under the subject of developmental period, as more data are 
available for the entire period than for any of the stages in this period. 
The observations which have been made upon the duration of the 
larval stage are tabulated and charted below (Table XXIV and fig. 9). 

Table XXIV. — Duration of the larval stage of the boll weevil. 




Fig. 9. — Diagram illustrating relationship of tem- 
perature to larval period of the boll weevil and 
showing range due to humidity. (Original.) 



Place. 


Year. 


Hatched. 


Pupated. 


Num- 
ber of 
larvae. 


Total 
number 
of larva 

days. 


Aver- 
age lar- 
val pe- 
riod. 


Mean 
tem- 
pera- 
ture. 




1902 
1902 
1902 
1904 
1907 
1908 
1908 
1910 


Sept. 6 


Oct. 5 


195 
15 
15 
88 

149 
50 
44 
98 


1,462.5 
142.5 
375.0 
1,100.0 
1,096.0 
435.5 
390.0 
618.5 


Days. 
7.5 
9.5 
25.0 
12.5 
7.3 
8.7 
8.8 
»6.3 


°F. 
78.7 


Do... 


Sept. 26. . 


Oct. 21 


73.6 


Do 


Nov. 11 


Dec. 12 


62.5 


Victoria, Tex. (ice box) . . 


\ug.2ii-Sept.3.. 




69.0 


Aug.26-Sept. 5.. 

July 18-29 

Aug. 3-19 

June 27-July 7. . . 

June 27-Nov. 11 . 


Aug. 28-Sept.7.. 

Aug. 1-12 

Aug. 17-31 

July 7-17 

July 7-Dec. 12.... 


79.9 


Dallas, Tex 


83.7 


Do 


84.1 


Tallulah, La 


79.1 






Total 


654 


5,620.0 


8.5 


76.2 









1 The extremes were 5.2 and 7.3 days. 



SEASONAL HISTORY. 



67 



PUPAL CELLS. 

As the larva becomes larger it gradually forms about itself a 
hardened black cell, composed of its cast skins and excrement. This 
cell is of a very tough leathery nature and seems to hold its moisture 
for a considerable period. In bolls the cell is even harder, as it 
becomes more or less mixed with lint and attains a considerable 
firmness, which often gives the cell the hardness and appearance of 
a seed. These pupal cells frequently include a portion of the hull 
of a seed, and it has also been found that the larva sometimes forms 
its cell within a single cotton seed. In these cells the larva trans- 
forms to the pupal stage. (See PI. IX.) 



to XT 



PUPATION. 

The formation of the adult appendages has progressed considerably 
before the last larval skin is cast. The wing pads appear to be nearly 
one-half their ultimate size. The formation of the legs is also dis- 
tinctly marked, and the old head shield ap- 
pears to be pushed down upon the ventral 
side of the thorax by the gradual elongation 
of the developing proboscis. Finally, the 
tension becomes so great that the tightly 
stretched skin is ruptured over the vertex 
of the head, and it is then gradually cast 
off, revealing the delicate white pupa. The 
cast skin frequently remains for some time 
attached to the tip of the abdomen. The 
actual period of ecdysis is about 45 minutes. 

THE PUPA. 



ACTIVITY. 




Fig. 10.— Diagram illustrating rela- 
tionship between temperature and 
the pupal period of the boll weevil 
and snowing variations due to 
humidity. (Original.) 



The pupal stage of the boll weevil is more 
or less an active stage. The pupa is so con- 
structed, with a forked prong at the posterior 
tip and with two strong tubercles on the thorax, as to have an axis 
upon which it can revolve without injuring its more delicate append- 
ages. As the cell is almost round, this movement of the pupa is more 
or less free in all directions and tends to make the cell harder and 
more durable. A person with acute hearing can detect the presence 
of a pupa by holding a square close to the ear. (See PL VI, c, d.) 



DURATION OF THE PUPAL STAGE. 

In general, it may be said that the length of the pupal stage is 
about equal to that of the larval stage minus the length, of the egg 
stage. This stage varies considerably, as do the two previous stages, 
the range being from 2 days at high temperature to 14 or more 
days at low temperature. During the winter it may be as long as 
several months. Table XXV and figure 10 are presented to illustrate 
the variations in the pupal period in their relationship to mean tem- 
perature. It may be stated briefly that the length of the pupal 
stage increases as the temperature decreases, and that the average 
humidity also influences the stage in the same manner. 



68 THE MEXICAN COTTON-BOLL WEEVIL. 

Table XXV. — Duration of the pupal stage of the boll weevil. 



Place. 


Year. 


Pupated. 


Emerged. 


Num- 
ber of 
pupae 


Total 
number 
of pupa 

days. 


Aver- 
age 
pupal 
period. 


Mean 
temper- 
ature. 




1902.... 
...do.... 


July 6-13 

July 12-18 

July 18-23 

July 24-25 

Sept. 15 


July 10-16 

July 16-22 

July 23-28 

July 29-30 

Sept. 20 


27 
22 
86 
23 

4 

5 
29 

4 
88 

1 

20 

141 

10 

50 


97 

84 
392 
111 

20 

24 
212 

56 

660 

5 

43 
717 

41 
167.5 


3.5 
3.8 

4.5 

4.8 

5 

4.S 

7.3 
14 

7.5 

5 

2.1 

5 

4.1 
i 3.3 


Degrees 
1 F. 


Do 




Do 


...do.... 


V 82. 65 


Do 


...do... 




Do 


...do.... 


79.05 


Do 


...do.... 


Oct. 21-24 

Nov.2-6 

Dec. 2-13 


Oct. 27-28 

Nov. 9-13 

Dec. 15-29 




Do 

Do 


...do.... 
...do.... 


69.2 
61.55 




...do... 


69 


Dallas, Tex 


1907.... 
...do... 






80.1 






Aug. 7-8 

Sept. 16-18 

Aug. 5-11 

July 14-21 


85.7 


Do 


...do.... 


Sept. 10-13 

Aug. 1-6 

July 7-17 


72.1 


Dallas, Tex 


1908.... 
1910.... 


84.5 


Tallulah, La 


79.1 






Total 


1902- 
1910. 


June 13-Dec. 13 


June 19-Dec. 29. 


510 


2, 629. 5 


5.1 


74.3 







1 The extremes were 2.8 and 3.9 days. 

PERCENTAGE OF WEEVILS DEVELOPED FROM INFESTED 

SQUARES. 1 

During the season of 1902 part of the many squares gathered in 
infested fields for the rearing of weevils were followed to learn some- 
thing of the percentage which produced normal adults. No exam- 
ination was made for those not yielding a weevil. The decay of the 
square during the period from its falling to the maximum time that 
must be allowed for weevils to escape normally so obliterates any 
small amount of work by a larva that it is difficult, even with exam- 
ination, to determine accurately the number of dead small larvae. 

Table XXVI.— Percentage of boll iveevils from infested squares. 



Locality. 



Approximate date. 



Number 

of 
squares. 



Number 

of 
weevils. 



Percentage 

of squares 

producing 

weevils. 



Victoria, Tex 

Guadalupe, Tex. 



Victoria, Tex. 

Do 

Do 



Do 

Total. 



July to August. 
August 



1903. 



June 

June to August 

August to September. 



June to September. 



1,125 
387 



334 
873 
368 



4,038 



360 
108 



106 
355 
192 



1,590 



32.0 
28.0 



32.0 
41.0 
52.0 



49.3 
39.4 



It seems safe to conclude that throughout the season fully one- third 
of the squares which fall after receiving weevil injury may be expected 
to produce weevils. 



» From Bui. 51, Bureau of Entomology, p. 92. 



SEASONAL HISTORY. 69 

LIFE CYCLE. 
DURATION OF LIFE CYCLE. 

We have shown that the average duration of the egg stage under 
different conditions is 3.7 days, of the larva 8.5 days, of the pupa 
5.1 days, of the preoviposition period 7.7 days, and of the oviposition 
period 31 days. Consequently, the average time from the deposition 
of the egg to the completion of oviposition by the resulting adult is 
56 days. The average required for the combined egg, larval, and 
pupal stages is 17.3 days. The larva requires about 2\ times as 
many days as the egg, and the pupa about two-thirds of the time 
required for the development of the larva. 

SEXUAL VARIATIONS. 

There are several factors which govern the duration of the life 
cycle of the weevil. The factor which is of least importance, if, 
indeed, it is of any importance, is that of sex. Mr. R. A. Cushman, 
in experiments at Tallulah, La., in 1910, in which squares were under 
more or less uniform climatic conditions, found that 475 males 
averaged in development 13.88 days, while 393 females averaged 
13.49 days. The figures are so nearly equal that there is great doubt 
as to whether the sexes require different periods. 

VARIATIONS DUE TO LOCATION OP DEVELOPING STAGE. 

As has been stated, the tendency of the squares to hang or fall 
is a determining factor in the length of the developmental stage. In 
a humid region, however, the difference may be very small. At 
Alexandria, La., in 1907, it was found that the average developmental 
period during the first 19 days of August in fallen squares was 15.3 
days and in hanging squares was 15.1 days. 

VARIATIONS DUE TO TIME OF FALLING OF INFESTED SQUARES. 

The period preceding the falling of the squares to the ground seems 
to be one of the strongest factors in determining the length of the 
developmental stages. To illustrate this, at Victoria, Tex., in August, 
1904, it was found that the average development in squares which 
hung only 1 day was 13 days, whereas for squares which hung 18 
days, the development was 28$ days; also at Dallas, Tex., in August, 
1906, the average development in squares which hung 6 days was 
19 days and in squares which hung 22 days was 36 days. We pre- 
sent Table XXVII, which shows in general that the difference in 
the time required for development in hanging and in fallen squares is 
proportionately the same in all months of the year and at all places 
where observations have been made. 



70 



THE MEXICAN COTTON-BOLL WEEVIL. 



Table XXVII. — Table to illustrate the effect of the time of falling upon the period of 
development of -the boll weevil in squares. 





^o. of days 
efore falling. 


Average period of development of weevils for eggs laid during specified periods. 


] 

b 


Victoria, Tex., 1904. 


Dallas, Tex., 1905. 


Dallas, Tex., 1906. 


Alex- 
an- 
dria, 
La., 
1907. 




June. 


July 

1-15. 


July 

15-30. 


Aug. 
2-11. 


Sept. 
10-29. 


Aug. 
12-28. 


Sept. 
11-30. 


Oct. 
2-3. 


June 
14-21. 


June29- 
July 0. 


July 

16-21. 


Aug. 
12-17. 


July 28- 
Aug. 19. 


1 


Days. 


Days. 
12.0 
13.5 
14.0 
14.4 
14.1 
15.6 
15.5 
18.9 
18.3 
18.7 
18.8 
20.8 
20.0 

22.0 
23.0 


Days. 
13.0 


Days. 
13.0 


Days. 
15.0 
13.0 


Days. 


Days. 


Days. 
25.0 


Days. 


Days. 


Days. 


Days. 


Days. 
12.5 


2 




13.2 
13.4 
14.5 
14.7 
16.0 
16.6 
16.6 
19.0 
19.7 


18.5 

21.7 










12 6 


3. . 


14.4 
14.0 
16.0 
18.0 
16.6 
17.6 
18.6 
30.0 
17.0 
23.0 
19.5 
20.0 




14.5 
16.0 
16.3 

16.3 
17.0 
16.0 


17.5 
16.0 
16.0 
18.5 


17.0 
15.0 
17.0 
17.0 
16.9 
17.6 
18.7 
18.6 
19.2 

19.0 
20.5 
19.0 
20.0 


19.0 
17.9 
19.5 
19.5 
21.4 
23.4 
24.0 
25.0 
24.8 
25.0 


12.3 


4 


14.8 
17.0 
16.0 
17.5 

20.6 
21.6 
22.0 
19.0 
24.0 
23.0 
22.0 


16.0 

15.0 
16.6 

19.6 
25.2 
21.5 
22.1 
25.2 
20.1 
23.7 
28.5 


15.0 
18.0 
19.0 
16.6 
18.6 
19.5 
22.3 
25.5 
22.0 
22.5 


13.5 


5 


18.7 

21.2 
28.0 


18.0 
26.0 


14.9 


6 


14.9 


7 


15.0 


8 


16.4 


9 


18.9 


10 






17.6 


11 






18.6 
23.0 


24.0 


21.2 


12 


19.5 


28.0 






13 




14 








18.0 


15 










23.0 






16 














17 






25.0 




25.6 










18 






28.5 


24.0 








35.0 
36.0 




19... 


















29.0 




20 
























21 . 
























35.0 
36.0 




22 








26.0 




















Average . . . 

of stages 
























No 


17.5 
36 


16.8 
123 


18.8 
25 


22.0 
62 


18.8 
58 


16.2 
69 


21.0 

17 


23.5 

4 


18.0 
20 


18.3 
9 


18.3 
69 


22.3 

85 


15.3 

87 



The average for the 664 stages covered in the table is 18.4 days, 
which may be taken as the general average period of development in 
squares. Figure 1 1 graphically illustrates Table XXVII. 



fO /S 2Q ZS 3 Q 



VARIATIONS DUE TO TEMPERATURE. 




It will be noticed that the average 
period of development in squares 
which have hung on the plant for 
the same length of time varies with 
the season, but an increase of tem- 
perature regularly lowers the aver- 
age developmental period. The 
following diagram (fig. 12) has been 
constructed from the average curves 
determined for each of the stages 
in the development and shows that 
the range is from 13 davs at 88° F. 
to 51 days at 62° F. 

By using the quantities deter- 
mined by the curves in figure 12 it 
is possible to chart the mean or nor- 
mal developmental period by months for any given place with 
known mean temperatures. This has been done on the following 
diagram (tig. 13) for Victoria, Tex., Ardmore, Okla., and Vicks- 



Fig. 11.— Diagram illustrating effect of time of 
falling of infested squares upon period of de- 
velopment of boll weevil at Victoria, Tex., 
August, 1904. (Original.) 



SEASONAL HISTORY. 



71 



burg, Miss. The curve obtained for Victoria is the widest which 
can be obtained in the United States with the exception of Texas 
points to the south of Victoria. It is interesting, however, that 




Fig. 12.— Diagram illustrating temperature control of developmental period of the boll weevil. 

(Original.) 



MAX. APR. M<4V *JUM£- UUiy AUG. jgHgT OCT. /VOX Q£TC. 




Fig. 13. — Diagram illustrating normal developmental period of boll weevil in squares, by mouths, at 
Victoria, Tex., Ardmore, Okla., and Vicksburg, Miss. (Original. > 



Pensacola, Fla., would show almost as wide a curve, but there the 
weevil would show less rapid development in the hottest months. 
The Memphis, Tenn., curve is slightly wider than that for Ardmore, 
Okla., and Dallas corresponds almost exactly with Vicksburg. It is 



72 



THE MEXICAN COTTON-BOLL WEEVIL. 



interesting to note that Ardmore shows only four and one-half months 
in which the developmental period can be under 30 days. Adding 
the preoviposition period to the developmental period, it is evident 
that unless the weevil adapts itself to the northern conditions latitudes 
north of Ardmore can have only a fraction over three generations in a 
year, whereas Victoria, with seven months in which the develop- 
mental period is less than 30 days, frequently has six generations. 



VARIATIONS OF DEVELOPMENT IN BOLLS. 



It is of interest to note the variation in development in bolls due to 
the length of time the boll hangs on the plant. At Victoria, Tex., in 
June the development was 15 days for a boll hanging 1 day and 39 
days for a boll hanging 26 days, while in bolls which did not drop, it 
frequently took over 60 days, with 67 as the maximum. The average 
developmental period of 67 weevils at Victoria and Dallas was 41 days, 
or more than twice the average period of weevils in squares. This 
difference may be considered as due to a combination of the factors of 
lower temperature, greater humidity, and less nutritious food. 



MISCELLANEOUS VARIATIONS. 



There are also some variations in development which can not be 
attributed to any of the causes cited above. Undoubtedly the insect 
adapts itself to the supply and condition of the food available. Con- 
sequently, under the same climatic conditions weevils in very small or 
delayed squares develop more quickly than those where the food is 
more suitable. Such variations are illustrated by Table XXVIII, 
which relates to the developmental periods of weevils of the third 
generation at Alexandria, La., in 1907. 

Table XXVIII. — Table showing variations in the developmental period of boll urevils 
in the third generation at Alexandria, La., in 1907. 



Date of oviposition. 



September 2. . 

Do 

Do 

Do 

Do 

September 1-4 
September 1 . . 
September 4. . 
Septembers.. 
September 3. . 
September 4-5 
September 1-5 
September 2. . 

Do 

Do 

Do 

September 3-4 
September 2-4 
September 2. . 
August 31 

Do 

Do 

September 1. . 

August 31 

September l. . 

August 31 

Do 

August 20 

Do 



Num- 
ber of 
stages. 



Total 
egg 
days. 



1 
4 

4 
7 
ins 
2 
3 
4 
4 

20 

00 

5 

10 

4 

24 



36 

18 

42 

9 

9 

4 

12 

12 

6 



Aver- 
age 
egg 

period. 



Total 
larva 
days. 



24 



10 
00 

210 
20 

112 
40 
72 
21 

144 
81 



Aver- 
age 
larval 
period. 



Total 
pupa 
days. 



Aver- 
age 
pupal 
period. 



28 



12 
50 
120 
45 
90 
10 
72 
15 
72 
27 



Total 
weevil 
days. 



12 
39 
26 
26 
130 
390 
70 
224 
56 
108 
42 
258 
120 



total 
period. 



SEASONAL HISTORY. 



73 



Table XXVIII. — Table showing variations in (he developmental period of boll weevils 
in the third generation at Alexandria, La., in 1907 — Continued. 

TOTALS AND AVERAGES. 



Date of oviposition. 


Num- 
ber of 

stages. 


Total 
egg 

days. 


Aver- 
age 

egg 
period. 


Total 
larva 
days. 


Aver- 
age 
larvel 
period. 


Total 
pu pa 
days. 


Aver- 
age 
pupal 
period. 


Total 
weevil 
days. 


Aver- 
age 
total 

period. 




229 
149 
141 

152 


436 


1.9 














1,090 


7.3 








Pupal period 






717 


5.0 
















2,198 


14.4 



















DEVELOPMENT OF WEEVILS IN THE SQUARES WHICH NEVER FALL. 

It is generally true that squares seriously injured by the weevil 
sooner or later fall to the ground. The form of the absciss-layer 
grown when the square is injured determines whether it is to fall 
or to hang. (See PI. XV.) This will be explained fully in connec- 
tion with the discussion of parasites (pp. 143, 144). 

Certain climatic and cultural conditions seem to increase the 
tendency of the cotton plants to retain the infested squares, although 
this tendency seems to be very largely of a varietal character. In the 
hanging position the square dries thoroughly and becomes of a dark- 
brown color. Although exposed to complete drying and the direct 
rays of the sun, the larva 1 within are not destroyed by the sun in the 
same proportion as those which are exposed to the sun on the hot 
soil. However, control b\ r parasites is much greater in the hanging 
squares than in the fallen squares — so much greater at times that the 
total mortality from all causes in hanging squares surpasses that of 
fallen squares. This matter will be dealt with more fully in a later 
section. 

Owing to the much smaller number of squares which hang on 
the plants, we have been unable to obtain a sufficiently large series 
of records upon the development of the weevil in this class of squares, 
but the records available show that the development is slightly 
shorter in hanging squares than in the average fallen squares. 



DEVELOPMENT DURING WINTER, 

As is normal with many species of weevils, there is some develop- 
ment during the winter months. This development, however, is 
frequently cut short by severe freezes. In southern Texas larvae and 
pupa? of the boll weevil which are in squares when frost comes are 
not always killed thereby, but slowly finish their development if the 
weather is warm enough for any activity, and the adults thus devel- 
oped may live through the winter without feeding. Mr. J. D. Mitchell 
took a number of live larva 1 , pupa?, and adults from bolls in a field at 
Victoria, Tex., on December 26, 1903, after two hard frosts and one 
freeze. Two weeks later, from a field in the same locality, after 
three hard frosts and two freezes (30° F.), he took another lot of 
live specimens in these three stages. On February 7, 1904, Mr. 
Mitchell took 32 adults, 1 pupa, and 4 larva 1 , all alive, from standing 
stalks, and on February 14 he found 32 adults, 2 pupa?, and no 
larvae. The material collected at different times up to February 14 



74 THE MEXICAN COTTON-BOLL WEEVIL. 

included 197 specimens, 23 larvae, 30 pupa?, and 144 adults. It is 
therefore evident that large numbers of weevils go into the winter 
in the immature stages, and there is every probability that, in the 
southern part of Texas at least, many of them live and mature, 
emerging m the spring. It may be that this gradual maturity of the 
hibernated weevils is one of the reasons why they emerge so irregu- 
larly from their winter quarters. 

Prof. Sanderson, in Bulletin 63 of the Bureau of Entomology, 
mentions that in March, 1903, Mr. W. P. Allgood sent aim from 
Devine, Medina County ,Tex., a quantity of bolls, which were examined 
March 12. Twenty per cent of the bolls contained weevils, alive or 
dead, in some stage. In 40 bolls there were 40 live and 11 dead 
pupse, 30 live and 40 dead adults, and 5 dead larva?. Many of the 
adults had just transformed from pupae. One live larva was found 
in the material. Estimating the survival of weevils in the plants in 
this field, Prof. Sanderson calculated that there would be about 10,500 
weevils per acre in the spring. The lowest temperature which the 
weevils experienced in the locality from which these bolls were sent 
was 23° F. in February. 

SEASONAL ABUNDANCE. 
BROODS OR GENERATIONS. 1 

The term "brood" can hardly be applied in its usual sense to the 
generations of the weevil, as was pointed out by Dr. L. O. Howard in 
the first circulars of the bureau dealing with the problem. For 
several reasons no line of distinction can be drawn between the genera- 
tions in the field at any season of the year, not even between hiber- 
nated weevils and the adults of the first generation. As has been 
shown, the period of oviposition among hibernated females is in some 
cases fully 3 months, while it averages 48 days. The average 
period of the full life cycle for the first generation is 25 days, and as 
the time for the second generation would be slightly less, it is evident 
that the first eggs for the third generation may be deposited at the 
same time as those for the middle of the second generation, and also 
with the very last of the eggs deposited by hibernated females for the 
first generation, as shown in figure 14. The great overlapping of 
generations thus produced prohibits the application of any of the 
common methods of ascertaining their limits. The complexity 
indicated for the first three generations becomes still further increased 
as the season advances, so that in October, for example, a weevil 
taken in the field might possibly belong to any one of five or six 
generations. Duration of life and the period of reproductive activity 
are important factors in determining the average number of genera- 
tions. Periods of greatest abundance can not be regarded as giving 
any reliable information upon this point, since the number of weevils 
developed soon comes to depend largely upon the supply of squares. 

In tiie case of the boll weevil, therefore, the information upon the 
number of generations must be drawn mainly from laboratory sources, 
but the results are supported by observations made in the field. Many 
of the hibernated weevils continue to deposit eggs until the middle of 
July, and some are active for fully a month longer. In 1903 the last 
eggs from hibernated weevils were deposited on August 27. In the 
course of rearing experiments made in 1902 it was found that many 

* The following two paragraphs are taken from Bull. 51, Bureau of Entomology, pp. 95, 96. 



SEASONAL HTSTOEY. 



75 



weevils which had become adult about the 1st of August would con- 
tinue to deposit eggs until the latter part of November. Considering 
the longest-lived weevils and their last-laid eggs, therefore, it is easily 
possible for two generations to span the entire year. The weevils 
developing after the middle of 
November may go into hiberna- 
tion, and from their last deposited 
eggs produce weevils whose last 
offspring will be ready for success- 
ful hibernation again. This con- 
clusion is based upon actual dem- 
onstration. 

The maximum number of gener- 
ations will be found by taking the 
first instead of the last eggs de- 
posited in each case. In order to 
ascertain the maximum number of 
generations which would be pos- 
sible, the figures for the develop- 
ment at Victoria, Tex., have been 
taken. Figure 14 is a diagram 
which shows the maximum num- 
ber of generations possible and also 
the minimum number possible. 
This is based upon the mean tem- 
peratures of the various months at 
Victoria and the known period of 
development at such mean tem- 
peratures. The maximum number 
of generations of course begins with 
the first egg laid by the first weevil 
to begin oviposition in the spring 
and continues with the first egg of 
the first developing weevil from 
each generation. In this manner 
it will be seen that 10 generations 
are possible for weevils reared on 
squares. The last egg laid by the 
first emerged weevil and the last 
eggs laid by the following genera- 
tions allow only three generations 
from the first emerged weevils, 
which might be considered the 
minimum. The maximum number 
of generations from the last emerg- 
ing weevils by the same system can 
only be eight generations, whereas 
the minimum number of genera- 
tions from the last emerged weevils 
will be two generations. 

There is no basis for the idea that there is a distinct hibernation 
brood. The activity of the adults and the development of the imma- 
ture stages is gradually retarded by the decline in temperature until 




76 THE MEXICAN COTTON-BOLL WEEVIL. 

hibernation time arrives. Most of the weevils of the first two or three 
generations have probably died, or then do so, while most of the 
adults of later generations, still having considerable vitality, go into 
hibernation. It is certain that every generation may have some 
direct part in the production of weevils which are to hibernate. All 
weevils which are still strong and healthy when cold weather comes 
on may be expected to go into hibernation, so that there can be no 
special brood for this purpose. 

POSSIBLE ANNUAL PROGENY OF ONE PAIR OF HIBERNATED WEEVILS. 

One of the most important factors in the development of an insect is 
its capacity for very rapid production. The conclusions as to the 
ability of the boll weevil in this respect are drawn from the following 
data, summarized from what has been set forth in preceding pages 
of this bulletin. The starting point is considered to be the average 
date of deposition of one-half of the eggs for the first generation at 
Victoria, Tex., which, under the usual conditions, seems to be about 
June 10. The average number of eggs deposited by a female was 
found to be 139. For the purpose of this computation 70 is the 
assumed number. The difference may be considered as an allowance 
for mortality or failure to hatch. The average period of development 
for each generation is 19 days. The average period between emer- 
gence of the adult and deposition of the first eggs is 6 days. The 
average period for the deposition of one-half the eggs for each genera- 
tion is 18 days, thus making the average period for each generation 43 
days. The sexes are produced in approximately equal numbers. 
For the sake of conservatism allowance has been made for only four 
generations in a season. The following table shows the rate of multi- 
plication and the corresponding dates: 

Annual progeny of one pair of hibernated weevils. 

Weevils. 

First generation, average adult June 29, numbering 70 

Second generation, average adult Aug. 10, numbering 2, 450 

Third generation, average adult Sept. 22, numbering 85, 750 

Fourth generation, average adult Nov. 4, numbering 3, 001, 250 

Total 3, 089, 520 

As a matter of fact, the multiplication during the early part of the 
season is so much more rapid that it is very certain that a large part 
of the third generation becomes adult by the middle of August. Pos- 
sibly a more definite idea of the significance of this ability for repro- 
duction may be obtained if we consider that, at the conservative rate 
given, the progeny from one fertile hibernated female might, in the 
course of four generations, number one weevil for every square foot 
of area in a 75-acre field. 

As a matter of fact, the possibility of the multiplication is controlled 
primarily by the abundance of food supply. The maximum infesta- 
tion is usually reached some time in August. If we assume that there 
are 6,000 plants on each acre of ground, and that each plant produces 
100 squares for weevil attack up to August 1, we would find that if 
the usual percentage of these squares produces weevils, the actual 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VIII. 




"* -' ; 



*=- si-.; 



fell . 




/■Vi/. a.— Newly planted cotton field, with sprouts from overwintered cotton roots. (Original.) 




Fig, !>.— Fallen infested squares. (Original.) 

Field Conditions in Territory Occupied by the Boll Weevil. 



SEASONAL HISTORY. 



77 



multiplication would be limited to about 250,000 weevils per acre. 
It has been shown in this bulletin that on the average over 50 per 
cent of the weevil stages are destroyed by natural conditions. This 
means that the theoretical possibilities are never reached. In fact, 
it is doubtful whether the actual increase from a single pair exceeds 
2,000,000. 

Prof. Sanderson, in Bulletin 63, of this bureau, estimated that the 
actual increase in the number of weevils from the 1st of June to the 
1st of September is about 50 times and certainly not over 65 times, 
where theoretically it would be 625 times. 



PROGRESS OF INFESTATION IN FIELDS. 

It is of considerable importance to understand the rate of increase 
of the infestation in the fields. Normally, in a given cotton field the 
infestation when the squares have just begun to form is under 10 
per cent, but this percentage increases very rapidly in proportion as 
the hibernation was successful. The infestation generally starts 
in a given field in the vicinity of timber or of buildings where cotton 
or cottonseed was stored during the winter. It then progresses in 
increasing circles until the entire field is scatteringly infested. From 
then on the increase is general until it is almost impossible to find an 
uninfested square. Table XXIX may be used to illustrate the 
progress of infestation in a given field. 

Table XXIX. — Progress of infestation by the boll weevil, field 1, Victoria, Tex. 1 



Block. 


1 lllli'. 


Number 
of 

squares, 
exam- 
ined. 


Number 

of 
squares 
infested. 


Percent- 
age. 


Remarks. 


I 
11 


1903. 
f June 8, 9 

July 13 

{July 22 

August 4 

(August 29 . 

fJuly30 

1 August 1 

) August 4 

(August 20 


4,200 
407 
249 
278 
91 
358 
331 
300 
699 


675 
211 

193 
224 
85 
168 
lis 
100 
636 


16.0 
45.0 
77.5 
80.6 
93.5 
46.6 
44.7 
33.3 
91.1 


Work of hibernated weevils only. 
Second generation at work. 
Third generation beginning. 

About four generations now working. 
Much cotton dying from root rot. 




Total . 


6,973 


2,440 


35.0 





i From Bull. 51, Bureau of Entomology, p. 114. 



78 THE MEXICAN COTTON-BOLL WEEVIL. 

Additional illustrations are .furnished in Table XXX. 
Table XXX. — Observations upon infestation bi/ the boll weevil, various localities, 1904. 1 





a 


A 




•6 


o A 


a 


ojjf 




o^ 


°?2 


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a 


a 

63 . 

-6 
o m 

a 

s~ o 




a 


v* 


> m 


- 3 


a . 


05 o 


aj a> 




Locality (Texas). 


3 . 
on 

£'*> 

°S 

<c X 
,C a) 


£ 
a 

o 

•a 


a 

X 

5 

a 1 


5? M 

8 1 

£ o 

<3 2 C3 


M 05 


^'3. 

8 a 

« ° 

o 

d5' 


«T3 

— Si 

o a 

»l 
■5 9 

S aj 

as 

_ o 


Mc3 

8 "3 

ftO r 

0) a; 


sg c - 

i » o 


03 03 

8 | 

o 3 
*- cr 

& a 

05 g 




a 


B 




3 




S as 


r g,ffi 


d^2 


l- ^ ^ , fc- ^ CJ 


05 




3 


3 










> ta S 




> OJ .C > o3*> 


> 




£ 


£ 




£h 


< 


EH 


< 


E-i 


« H 


< 








1904. 




















12 


2 


Aug. 23 to 
Sept 9. 


2,754 


94.0 


251 


9.1 


1,175 


94.7 


1.8 


4.2 






Corsicana: 
























A 


12 





July 29 to 
Sept. 12. 


6,951 


72. 4 


376 


5.7 


2,506 


71.9 


.6 


27.0 






B 


11 





July 28 to 
Sept. 12. 


4,534 


80.4 


407 


9.0 


3,261 


64.9 


.6 


19.0 








15 


5 


July 30 to 
Sept. 13. 


6,445 


64.4 


317 


5.0 


4,618 


64.9 


1.2 


34.5 








22 


2 


Aug. 26 to 
Sept. 14. 


3,719 


91.3 


274 


7.4 


2,456 


92.8 


.7 


8.2 








11 


18 


June 18 to 
Sept. 24. 


13,227 


54.2 


170 


1.3 


544 


66.9 


6.1 


44.6 






Wharton 


4 


4 


July 22 to 


5,005 


65.0 


167 


3.3 


230 


46.4 


10.2 


25.3 








Aug. 25. 

June 18 to 
Sept. 24. 


















Total 


87 




42,635 




1,962 




14,790 




















6 






70.1 




4.6 




80.0 


2.2 


27.7 













1 From Bull. 51, Bureau of Entomology, p. 116. 

Prof. Sanderson 1 has estimated that usually 50 per cent of the 
squares will be punctured by about two months after the cotton com- 
mences to square, at which time there would normally be about 100 
squares to the stalk. When one-half of the squares are punctured it 
may be readily concluded that there are probably sufficient weevils 
present to prevent any more squares from forming fruit. It will be 
seen, therefore, that the critical period in the relation between natural 
increase of squares on the plant and increased injury by the boll 
weevil is during the period of six to eight weeks after the first squar- 
ing, which usually coincides more or less closely with the time between 
the appearance of the second and third broods of the weevils. Thus, 
if we consider six weeks as the average time for cotton to begin to 
square after planting, it will be seen that the bulk of the fruit must 
be set in 85 or 95 days after planting. In other words, to escape 
injury by the boll weevil, cotton must be so grown that the bolls will 
commence to open in about 100 days after planting and that all the 
fruit which will probably be secured must be set within 45 days after 
the squares begin to form. The advantage of early planted cotton 
and rapid-maturing varieties becomes, therefore, very apparent. 

Field examinations have shown that the period of maximum infes- 
tation is reached between August 1 and 20, and that from 6,000 to 
10,000 adult weevils per acre is sufficient to cause maximum infesta- 
tion within a few days. The highest number of weevils per acre which 
has ever actually been recorded from a locality during the summer was 

1 Bull. 63, Bureau of Entomology, p. 38. 



SEASONAL HISTORY. 



79 



24,347 adult weevils at Port Gibson, Miss., in August, 191 1. 1 With 
this number of weevils there was a record of only 37.03 per cent infes- 
tation of the remaining squares and bolls. Higher percentages of 
infestation have been recorded witli much smaller numbers of adult 
weevils per acre. 

EFFECT OF MAXIMUM INFESTATION UPOM WEEVIL MULTIPLICATION. 

At the time of maximum infestation the majority of the third- 
generation weevils are becoming adult and many of the hibernated 
weevils have died. About this time also a decrease in square pro- 











































i ~r^ 






- 


































Ttth 












' Su re 


~\^\<^\\V-\W\ 










jQ^V/fX. y^?L\\jl JX^m VYV 








~i 
































rA/V y> 








k^Q^m^ 








-)w 




^ V.i 


rsfb 












I / 1 


s 





Fig. 15, 



-Status of the boll weevil in Texas in August, 1900; percentage of infestation of all forms. 

(Original.) 



duction accompanies the maturity of the bulk of the crop, owing to 
the fact that the assimilative power of the plant is largely consumed 
in maturing seed. If dry weather occurs at this period, which is 
frequentlv the case in Texas, there is a further decrease in the number 
of weevils present. Not only are there fewer squares to become 
infested, but each square is also subjected to greater injury, and many 
which would otherwise produce weevils are unfitted as food for the 
larvae by the decay which follows the numerous punctures. Several 
eggs may be deposited in each square, but as a rule only one weevil 



' During the late fall the number may be much larger. See p. 76. 



80 



THE MEXICAN COTTON-BOLL WEEVIL. 



will develop. These general, conditions frequently bring about a 
reduction of the number of weevils present in the field. This becomes 
evident to the planter by the number of blooms seen. Of course, the 
conditions soon change and the weevils become more abundant than 
before. 



STATUS EXAMINATIONS. 



In order to become fully acquainted with the conditions of the weevil 
during the most important parts of the season, it has been the custom 
to conduct an extensive series of observations in the latter part of 




Fig. 16.— Status of the boll weevil in Texas in August, 1908; percentage of infestation of all forms. 

(Original.) 

June and first part of July and again in the first half of August in 
order to learn the extent of damage being done by the weevil. These 
examinations have been made so thoroughly and have been distrib- 
uted in such a manner that it has been possible, even in June, to 
determine the probabledirectionof the greatest movement of the weevil 
during the season, to point out the regions in which the damage to 
the crop will be greatest, and also to indicate where the control of the 
weevil during the winter has been of greatest consequence. The 
first "status" of the year frequently gives veiy definite evidence of 
natural control or an absence of it. While certain general methods of 



SEASONAL HISTORY. 



81 



control have been contrived, it is still true that some of the most 
important methods of control are those which are devised to suit 
particular emergencies. These have been indicated from time to 
time in connection with the status reports. 

RELATION OF WEEVILS TO TOP CROP. 

After considerable cotton has been matured fall rains often stimu- 
late the production of a large number of squares, and many planters 
are misled by the hope of gathering a large top crop from this growth. 

























1 






^ TTVwXyrvv^ ^"""~ 








/ 1 1 J l-p-OKii 1 




^^w^-S^S 




ZrYiJFcS^^^rKk 




\ : 


^yR^^fi^^&i 










<^(~ 


Ti — h /~~sf \j c\ IT. /lOkt/ 










iCjyJ^X^T^ 










^ 2&r 


\J A ^y 











Fig. 17.— Status of the boll weevil in Texas in August, 1909; percentage of infestation uf all forms. 

(Original.) 

The joints of the plant are short, and the squares are formed rapidly 
and near together. Though weevils may have been exceedingly 
numerous in the fields, their numbers will have become so decreased 
by the dispersion and by the limited quantity of food that they can 
rarely keep up with the production of squares at this period of rapid 
growth. Many blooms may appear, and the hope of a large top crop 
increases. It has been a very rare occurrence that planters have 
gathered top crops, even in years of no injury from insects. 

The chance of its development, though always small, becomes prac- 
tically inconsiderable wherever the weevil is present in numbers. 
28873°— S. Doc. 305, 62-2 6 



82 



THE MEXICAN COTTON-BOLL WEEVIL. 



In the senior author's experience of 10 years only one example of a top 
crop in a weevil district has been seen. This happened in the vicinity 
of Brownsville, Tex., in 1911. The production of a few bolls on the 
tops of the plants was due to a rare combination of exceptional influ- 
ences, including very dry weather during the summer, defoliation at 
an early date by the cotton worm, and late rains after the weevils 
were greatly reduced in numbers. 

Neither the very remote chance of gathering a top crop nor the 
actual injury which is being done to the crop of the succeeding year 
by allowing that growth to continue until frost kills it is generallv 



























L /$/^~? 








































w \^^y 






















& 










/\p 


4A^A\^XA 
























yywy^w^x\\ 














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5 



Fig. 18. — Status of the boll weevil in Texas in August, 1910; percentage of infestation of all forms. 

(Original.) 

appreciated by planters. Because of the apparent abundance of 
squares and the presence of many blooms the plants are allowed to 
stand long after they might have been destroyed to the great benefit 
of the next crop. As is the case in the early spring, however, the 
abundance of squares increases greatly the production of weevils, 
and though a few bolls may set, they are almost certain to become 
infested before they reach maturity. Every condition, therefore, 
contributes to the production of an immense number of weevils very 
late in the season and at just the right time for successful hibernation. 
As a result, far greater injury is done to the crop of the following 



SEASONAL HISTORY. 



83 



season with no actual gain in the yield of the current season. Plants 
standing until frosts kill them are often allowed to remain throughout 
the remainder of the winter and easily furnish an abundance of favor- 
able hibernating places for the weevils. The consequence of this 
practice is that so many weevils are carried through the winter alive 
that the yield of the next year is much less than it might have been 
but for the farmer's indulgence of the forlorn hope of a top crop. It 
is far wiser to abandon the uncertain prospects of a top crop and 
destroy the stalks in order to insure a better crop the following year. 




Fig. 19.— Status of the boll weevil in Texas in August, 1911; percentage of infestation of all forms. 

(Original.) 



VARIATIONS IX ABUNDANCE OF THE WEEVIL FROM YEAR TO YEAR. 

The decrease in damage by the weevil in Texas in the last few years 
has led some observers to believe that the insect will finally disappear 
altogether. Investigation shows that this belief is erroneous. In 
1897 the French entomologist, Dr. Paul Marchal, published a paper 
which set forth some of the essential factors governing insect abun- 
dance from year to year. This author called attention to the more 
or less regular periodicity in the abundance of certain well-known 
injurious insects. In this country the cotton leaf worm, Alabama 
argillacea Hiibner, is an example of such periodical abundance. The 



84 



THE MEXICAN COTTON-BOLL WEEVIL. 



application of Dr. Marchal's law to the abundance of the boll weevil 
will be discussed in the folio wi'ng paragraphs. 

When the boll weevil entered the United States, it was released 
from most of its natural enemies and was in the portion of the cotton 
belt most resembling its natural home. Naturally, it increased with 
great rapidity. In fact, the weevil was on what may be called the 
upward curve of numerical abundance from 1892 to 1896. In the 
meanwhile, native parasites began to adapt themselves to it, and we 
may assume that their abundance might be indicated by a curve par- 
allel to but behind that of the boll weevil. In 1896 a severe drought 
was the cause of a very sudden decrease in the numbers of the weevil 
and of course also acted upon the parasites. Following 1S96 the 
increase in abunclance of the weevil was comparatively slow, owing to 
the unlimited opportunities for spread. The maximum point in this 
increase appears to have been reached in the autumn of 1904 and 
may have Tbeen partly due to the fact that in that year the abundance 
of the parasites was on the decrease. In the winter of 1904 a severe 
cold period turned the curve of abundance downward, but the decrease 
was slow until the fall of 1907, when another severe freeze caused a 

sudden falling off. 
Floods in the spring 
of 1908, drought in 
the summer, a freeze 
in the fall of the 
same year, and 
droughts in the sum- 
mers of 1909, 1910, 
and 1911, followed 
in 1909 and 1910 bv 
severe winters, all 
combined to reduce 
the weevil still more. 
On the other hand, 
from 1904 to 1908 
the influence of the 
parasites was in- 
creasing and from then until 1911 decreasing. As Dr. Marchal 
pointed out, it is very rare that some condition does not intervene 
just before the number present has reached zero and save the species 
from extermination. The weevil will undoubtedly frequently be 
greatly reduced in large regions, but in such areas the inflow from 
other localities will serve to bring about earlv reestablishment. (See 
%. 20.) 

Undoubtedly the adverse seasons of recent years will be followed 
by others which will allow the weevil to reach approximately its 
former abundance. This alternation of years of scarcity and of 
abundance will continue indefinitely. Naturally, no definite predic- 
tion can be made as to the number of years which will be included in 
the alternating periods. 

The series of Texas maps presented herewith (figs. 15-19) illus- 
trates the variations in the percentage of infestation in August during 
a series of years in which the weevil abundance was at a low ebb. 
They also show very plainly how the areas of heavy damage are 
shifted by more or less local causes. 



&/oo 

^ 70 

\so 

%30 

£.20 



% 
& 

5 


5 


1 

3? 


1 






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1 




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5? 


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4 



Fig. 20.— Curves of numerical strength of the boll. weevil and its para- 
sites. The boll weevil curve is at the scale of 2 to 10 and represents 
the percentage of infestation in August in Texas. The parasite curve 
is at the scale of 1 to 1 and represents the percentage of mortality of 
the boll weevil due to parasitism. (Original.) 



NATURAL DISSEMINATION. 



85 



The status examinations upon which these maps were based show 
the following average percentages of infestation in Texas. (See Table 
XXXI.) 

Table XXXI. — Percentage of infestation by the boll weevil in Texas in August; years 

1906 to 1911. 



Year. 


Percentage of 
infestation. 


1900 
1907 
1908 
1909 
1910 
1911 


50.11 
38.09 
32.32 
14.78 
20.79 
1.12 



NATURAL DISSEMINATION. 

The natural movements of the boll weevil are of several more or less 
distinct kinds. For several months in the spring there is a general 
dispersal in search of food. After the cotton commences to square 
there is a steady spread across the fields from the vicinity or the 
places where the insects have hibernated. This may become a 
spread from field to field. In late summer there is a sudden and 
wide dispersal, which is shortly followed by a search for hibernation. 

SPRING SEARCH FOR COTTON. 

After a quiescent period of from five to eight months the weevils 
leave their hibernation quarters and start in search for food. During 
a warm period, such as was experienced in March, 1907, many weevils 
come out of hibernation long before any cotton has made its appear- 
ance. Without doubt these weevils wander considerable distances 
and finally either die or reenter the quiescent state on account of 
lower temperatures. As the emergence from hibernation covers a 
period of about three months there is little or no regulation of the 
direction of flight, such as might occur if all emerged at the same time 
during a high wind. Elaborate tests have been made by releasing 
marked weevils fresh from hibernation in the vicinity of cotton fields. 
Invariably after careful search a very small percentage of these wee- 
vils have been found in the nearest cotton. 

The experiments of Mr. A. C. Morgan in 1906 at Victoria, Tex., 
give the most specific data on individual flight. Seven hundred and 
eleven weevils were used in the experiments, of which 355 had been 
fed and 356 were unfed. Of the fed weevils 179 were male and 176 
female, while of the unfed weevils 183 were male and 173 female. 
This gave a total of 362 male and 349 female weevils. The maxi- 
mum flight by a fed male was 775 yards, by a fed female 350 
yards, by an unfed male 225 yards, and by an unfed female 500 
yards. The experiments also showed the average distance per 24 
hours for a fed weevil as 63.3 yards, and for an unfed weevil, 66.6 
yards. It was generally observed that the weevils flew with the 
prevailing wind. 

Observations on the early spring movement of the weevil in Mis- 
sissippi in 1910 showed the utility of the rotation of crops. During 



86 THE MEXICAN COTTON-BOLL WEEVIL. 

the two status examinations made in 1910 in southern Mississippi 
it was very evident that in these fields in which cotton followed corn 
there was a conspicuous absence of infestation until the fall dis- 
persion of 1910, whereas in neighboring fields in which cotton fol- 
lowed cotton the infestation was in some cases extremely high, even 
in June. 

These circumstances and many others which have been observed 
in the spring indicate a rather irregular dispersal from the places of 
hibernation which may carry the weevils considerable distances in 
all directions. On the extreme border of the infested territory this 
may result in the infestation of entirely new territory. 

SPRING SPREAD WITHIN THE FIELD. 

The spread from plant to plant begins in the portions of the field 
adjacent to favorable hibernation quarters. It has usually been 
found that the early summer infestation begins at a point adjacent 
to timber or near farm buildings where seed or seed cotton has been 
stored. From these centers it is generally easy to trace the infesta- 
tion to other parts of the field. The movement of the weevils from 
these centers, however, is not regular. They occasionally fly to 
rather distant portions of the field and then start new centers, but 
on the whole the progress is steady and soon brings about a complete 
infestation of the field. 

A number of observations were made to determine the degree of 
movement of hibernated weevils in a field at Victoria, Tex., in 1904. 
The weevils were marked so that they could be recognized, and 
frequent examinations were made to determine the location of each 
specimen from day to day. 1 It was found that the maximum time 
one weevil remained upon a single plant was 18 or more days, the 
observations having been discontinued after the eighteenth day. 
The average time positively found in 73 cases was 4 days, with a 
possibility for this same number of observations of 6§ days. Prob- 
ably a true average lies approximately between these results, and, 
if so, we may assume that about 5^ days usually intervene between 
the movements of each weevil. In the whole series of observations, 
extending over 25 days, for weevils which were found after being 
liberated, only 57 movements were recorded. The total of these 
movements averaged only 62 feet each in 177 movement days. This 
would give us an average movement of but 0.35 foot per day for each 
weevil in a field where stubble plants were quite abundant, where 
squares were forming upon fully one-third of the plants, and during 
a period for which the mean average temperature was 78.6° F. 

SUMMER FLIGHTS. 

During the summer there is more or less general movement within 
the cotton fields and also from field to field. These flights are at 
first weak, but gradually become more pronounced and finally lead 
into the great dispersal of the late summer and fall. 

During the summer the conditions on the border of the infested 
area are peculiar. Many of the weevils which arrived late in the fall 
«•!' the preceding year are unable to survive the winter on account of 

i The remainder of this paragraph is from Bulletin , r >l, Bureau of Entomology, p. 112. 



NATURAL DISSEMINATION. 87 

their exhausted condition. Therefore, the line of continuous infesta- 
tion may be considerably behind the line of continuous infestation 
resulting from the last movement of the preceding year. Outside of 
this continuous line is a strip of considerable width in which the 
weevil is found scatteringly. The summer nights cause these isolated 
infestations to coalesce. 

FALL DISPERSION. 

All movement of the weevil at other seasons is insignificant in 
comparison with the great dispersion of the fall which carries the 
insect far into new territory. It is this movement which causes the 
more or less regular annual advance in the cotton belt. In one 
sense this dispersion is merely an overflow from territory in which 
the insects have become so numerous that there remain no oppor- 
tunities for breeding. In another sense it appears to be the result 
of a strong instinct which the weevils possess to invade new regions. 
At any rate, they show great activity in the late summer and fall. 
The main causes of the fall flight, therefore, appear to be (1) a 
scarcity of food and breeding places due to maximum infestation, 
and (2) an instinct to invade new territory. Several conditions 
may tend to precipitate the movement or strengthen it. Among 
these are damage by other cotton insects, which hastens maximum 
infestation, and drought, which may have the same effect by pre- 
venting the continued fruiting of the plants. 

There seems to be no special tendency to fly in any particular 
direction, although prevailing winds frequently cause the majority of 
the insects to follow one course. This has been observed to be 
southeast, north, and east in different localities. If not governed 
by the wind, any weevil which takes flight is as likely to fly toward 
the old infested territory as in any other direction. It is, therefore, 
only a portion of the dispersing weevils which enlarges the infested 
territory. 

The distance any weevil will fly in this movement depends upon 
how soon it finds uninfested cotton. If on the first flight it finds only 
heavily infested cotton or none at all it will take wing again. In this 
way a succession of flights may carry the insect over a wide territory. 
In one case a distance of over 40 miles has been known to be cov- 
ered in this manner. If, on the other hand, the first flight carries 
the weevil into an uninfested field it remains there. Consequently, 
the advance is slowest in regions where cotton fields are numerous. 
The occurrence of the leaf worm, Alabama argillacea, in great numbers 
in any locality destroys the food and tends to cause decidedly longer 
flights of the dispersing weevils. 

So far as we have been able to discover, the weevil has no sense by 
which it can locate cotton. Such a sense may exist, but the general 
aimless flight of thousands upon thousands of individuals seems 
sufficient to account for the infestation of all fields in new territory. 
An interesting observation was made by the junior author and Mr. 
G. N. Wolcott near Meridian. Miss., that the early dispersing 
weevils, in flying through hill country with heavy woods, found 
only the patches on the tops of the hills and from these gradually 
spread downward to the denser cotton. 



THE MEXICAN COTTON-BOLL WEEVIL. 




NATURAL DISSEMINATION. 89 

The fall movement of the weevil has been studied carefully each 
year since 1904. (See fig. 21.) The circumstances have been differ- 
ent each season, but with uniformity within certain limits. Several 
examples will be given. In the fall dispersal of 1904 the weevils 
seemed to have crossed the line of continuous infestation in southern 
Louisiana about August 1, and a little later toward the north, but 
in all cases the movement had crossed the line by the 20th of August. 
In this year there were two very well-defined dispersals with about 
a month intervening. This might indicate that the first dispersal 
was caused by the lack of food and that in another month a new 
generation found itself confronted by the same conditions as its 
predecessor and was also forced to disperse. 

In 1906 the movement seems to have been more irregular, for the 
first serious new infestation was in central Louisiana rather than 
in the southern part of the State. In the light of present knowledge 
this was probably due to the smaller amount of cotton grown in the 
pine woods of southern Louisiana, which naturally gave rise to 
comparatively few weevils for the flight. The year 1906 was the 
last in which any appreciable movement into western Texas was 
observed until 1910. 

In 1907 and 1908 the eastward and northeastward progress of 
the weevil carried it far into regions wdiere much cotton is produced. 
The year 1909 exhibited some very striking features. There had 
been a considerable loss in the infestation during the winter of 1908 
in northern Louisiana and eastern Arkansas, a region of very exten- 
sive cultivation of cotton. During the autumn of 1909 the almost 
continuous movement in southern Mississippi from field to field in 
the rather sparsely cultivated areas amounted to 120 miles for the 
season. In the delta region of Louisiana, Mississippi, and Arkansas, 
where the weevils encountered a belt of extensive cotton culture from 
which they had been driven back during the previous winter and 
were stopped by the large amount of food available, they were 
unable to gain more than 20 miles of new territory. 

In 1910 a peculiar situation developed. It was discovered that 
high winds had caused an extensive movement into central Mississippi 
in May or June. In the entire history of the weevil there had pre- 
viously been known but one occasion when a severe storm caused 
a dispersal of the insect. A study of the records of the Weather 
Bureau brings out the fact that there was a series of cyclonic storms 
about May 7, 1910, passing northeastward across Mississippi from 
the heavily infested regions around Natchez. We have been unable 
to find any other explanation of such an extensive movement in the 
early spring. Studies conducted during the summer and fall of 1910 
revealed the existence of many sporadic infestations throughout 
central Mississippi, probably due to the storm. From these isolated 
infestations the weevils spread in concentric circles until about the 
end of November, when the intervening territory became covered. 

The winter of 1909-10 was unfavorable to the weevil in the Delta. 
When the dispersion season opened it was noticed that in strong 
contrast to the rapid movements in central Mississippi, the weevils 
in the Delta advanced slowly. During the entire season there were 
only two courses of considerable movement in the Delta region. One 
of these was along the Mississippi River through the fields adjoining 
the levees. The other extensive movement in the Delta country 



90 THE MEXICAN COTTON-BOLL WEEVIL. 

was in a belt coincident with a strip known locally as the "dogwood 
ridge." 

The winter of 1910-1 1 also w T as unfavorable to the w r eevil. It began 
with a sudden freeze on October 29, wiiich extended over almost the 
entire infested region and destroyed the food supply. Severe cold 
weather in January also contributed to the control. Examinations 
made in June and August, 1911, demonstrated that the w T eevil was in 
the lowest average condition numerically that it had ever reached. 
It was completely exterminated in the northern portion of the Texas 
and Oklahoma black prairie, but w r est of this was a region which 
escaped the first frost, and wiiere the w T eevils occurred in more or less 
normal numbers. 

The defoliation by the leaf worm was so widespread that a condition 
of maximum infestation was reached with much smaller numbers of 
weevils than usual, and the scarcity of proper food supply forced a 
phenomenal advance along the Mississippi Kiver toward Tennessee. 

In Texas and Oklahoma there were some gains made in the lost 
territory, but even with these gains 24,000 square miles of territory 
were not reinfested. The northern limit of cotton production in 
western Arkansas w r as reached, and the line of infestation stopped 
only about 10 miles short of the southwestern corner of Tennessee. 
Great gains were made in northern Mississippi, and w r estern Alabama 
and Florida became invaded for the first time. 

HIBERNATION FLIGHT. 

The fall dispersion movement continues more or less regularly 
until frosts occur and mark the beginning of the hibernation period. 
Thus, in many cases the fall dispersion is a flight into winter quarters. 
However, a period of feeding seems to be necessary for successful 
hibernation. Therefore, few of the dispersing weevils which are 
forced into hibernation by cold weather survive. Those that do 
survive seem to be supplied from a distinct movement into hibernation 
quarters at the end of the season. The most striking observation 
on this point was made by Mr. J. D. Mitchell in the winter of 1906. 
Although there had been no lowering of the temperature, he found 
on entering the cotton fields on November 18 a very restless activity 
among the weevils. Adults were observed upon the squares with 
their wings open and flew at the least disturbance. He observed 
many hundreds of weevils rising into the air and disappearing. The 
weather was warm and pleasant, and there appeared no reason at the 
time for this flight, winch continued for about two days. In a few 
days the temperature became decidedly lower, and Mr. Mitchell was 
able to find only a very few weevils remaining in the fields. This 
note is of special interest in connection with the observations on cli- 
matic control, which will be discussed later. 

OTHER FORMS OF NATURAL SPREAD. 

Heavy windstorms, hurricanes, and cyclones are powerful agents 
in the spread of the weevil. It is believed that the great storm of 
September S, 1900, in Texas, carried the infestation northward many 
miles. As has been stated, the storms of about May 7, 1910, in Missis- 
sippi, were instrumental in causing a considerable increase of the 
infested territory in that State. 



ARTIFICIAL DISSEMINATION. 91 

There is another method of natural spread of some local importance. 
In hill lands, especially, rains sweep immense numbers of infested 
squares to the lower parts of the fields. Cotton squares are remark- 
ably impervious to water, and weevils may develop in them after 
decay is far advanced. These squares may be carried many miles 
from their source and deposited under favorable conditions for the 
emergence of the weevils. 

ARTIFICIAL DISSEMINATION. 

While the natural dispersion of the boll weevil is by far the most 
important means by which new territory becomes invaded, there are 
certain artificial means of dissemination which are of some importance. 
The more noteworthy of these are connected with the handling of the 
cottonseed and cottonseed products. Many weevils are carried to 
the gins with the cotton. From the gins dissemination may take 
place in several ways. The weevils may be carried back to the farms 
in cottonseed to be used for planting, or they may be shipped by rail 
to the oil mills along with the seed. Moreover, weevils are likely to 
secrete themselves during cool weather in the wrapping of cotton bales. 
In this manner transportation along with the lint is possible, although 
experience has shown that the danger from this source is inconsid- 
erable. When the cottonseed arrives at the oil mill there is chance 
of infestation from flight into neighboring cotton fields. The greater 
damage, however, is in the shipment of weevils beyond the oil mills 
in the cars which have been used for the purpose of carrying the seed 
to those establishments. 

Among the means of minor importance may be mentioned the inci- 
dental carriage by vehicles, including railroad coaches, by the move- 
ment of plantation laborers, and by intentional carriage for the 
urpose of experimentation or exhibition. The possibility of spread 
y these various means will be discussed in the following paragraphs: 

MOVEMENT OF SEED COTTON. 



i! 



Many immature or teneral weevils are carried to the gins with the 
seed cotton. Adults are frequently found crawling over the wagons 
filled with unginned cotton. The devices for removing foreign matter 
from cotton in the process of ginning are numerous and effective. 
Many of the weevils are removed or destroyed, but adults, as well as 
larvae and pupae, are likely to pass through the gin with the seed. 
This has been determined by the Bureau of Entomology by running 
gins experimentally. 1 Many of the weevils, consequently, are carried 
into the seedhouse along with the cottonseed. Moreover, many of 
those that are removed by the cleaning devices are not injured. They 
pass along with the motes into a barrel or box, winch is generally 
uncovered, and from there they frequently fly about and find their 
way into the cottonseed, or they may secrete themselves in the 
bagging of the bales standing in the gin yard. Furthermore, many of 
the adult weevils are not taken into the gin house at all. Being on 
the cotton in the wagon, they are disturbed by the process of unload- 
ing and may fly to any portion of the plant. Consequent 1)*, cotton- 
seed in storage at the gin may become infested by any one of the 

1 For a full account of these experiments see Farmers' Bulletin 209. 



92 THE MEXICAN COTTON-BOLL WEEVIL. 

following means: (1) By passage of weevils through the gins along 
with the seed; (2) by the weevils finding their way into the seed 
house from the receptacle containing the discharge from the cleaner 
feeder; and (3) by flight from the wagons during the process of 
unloading. Thus, gins may serve as important agencies in the dis- 
semination of the boll weevil by the shipment of the seed or possibly 
of baled cotton. That the danger in baled cotton is slight is shown 
by the fact that no colonies have been found to have become estab- 
lished in spite of extensive shipments out of the infested territory 
which have been made for several years. 

In many localities the unginned cotton is carried for a distance of 
20 miles or more to the gins. It frequently happens that this car- 
riage is into uninfested territory. Under such conditions it is evident 
that an important form of artificial dissemination of the weevil 
occurs. Two examples will be given of the possibility of the dissem- 
ination of the weevil by such means. In October, 1904, a shipload of 
unginned cotton was carried across Lake Calcasieu, La., from Grand 
Lake and Lakeside to Cameron. The latter place was free of the 
weevil and isolated by extensive stretches of swamp lands. Shortly 
after the shipment reached Cameron, however, an infestation was 
found in the gin yard. It was in all probability due to the carriage 
of the cotton from the opposite side of the lake. In the other case a 
shipment of unginned cotton was made from Yucatan, Mexico, to 
Mobile, Ala., in 1909. The Mexican locality was infested by the 
boll weevil, while the region about Mobile was free of the insect. No 
infestation resulted in this case for the reason that the shipment from 
Mexico was accidentally delayed in transit and did not reach Mobile 
until all of the weevils had died. If the shipment had been made 
according to the regular schedule there is little doubt that an infesta- 
tion in the vicinity of Mobile would have resulted. 

MOVEMENT OF COTTONSEED. 

In ginning districts on the edge of the infested territory the custo- 
mers are composed of those whose fields are infested and those 
whose fields are not infested. The inevitable result is that weevils are 
constantly brought into the gin yards by the farmers, and in the subse- 
quent movements of the cotton are spread broadcast. Some of them 
may alight upon the wagons filled with the seed to be returned to the 
farm and consequently may be frequently carried to uninfested 
farms. The most striking illustration of infestation by this means 
was found in Shelby County, Tex., in 1904. An establishment on 
the border line ginned for farmers in a radius of 10 miles or more. 
Some of the customers had the weevil. The ginner himself had a 
few weevils on his place, but had raised an exceptionally large crop 
of big-boll cotton, for the seed of which quite a demand arose. An 
investigation of the farms in this district showed that all the custo- 
mers who had purchased this seed had infestations near their seed 
house. Very few of the other farms in the vicinity were found to be 
infested. 

Cottonseed is frequently shipped considerable distances from the 
gins to the oil mills. As has been shown there are abundant chances 
that the seed may become infested at a gin within the infested terri- 
tory. (See Plate IX.) At the oil nulls the cars are unloaded and 



Bui. 114, B'jreaj of Entomology, U. S. Dept. of Agriculture. 



Plate IX. 




Relation of Boll-Weevil Cells to Seed. 

a, Boll-weevil pupa found in cotton seed; b, boll-weevil pupa in cell of lint from boll: c, weevil 
ct'll in dwarfed cotton boll containing live pupa taken among seed; d, weevil cells in bolls; 
i, cotton seeds. (.Original.) 



ARTIFICIAL DISSEMINATION. 



93 



passed on to the railroads for other uses, frequently without being 
swept out at the mills. It is common in the lumber country for cars 
to pass from oil mills to lumber mills. Such cars are often found 
containing several pounds of seed in the corners. The lumber men 
sweep out this waste before loading their cars. In case cotton grows 
near the mill the danger is quite apparent. 

An interesting example of the shipment of the weevil in cotton- 
seed came to notice in Mexico a few years ago. 1 On January 5, 1903, 
it was discovered that Texas-grown cottonseed was being imported 
into the southeastern part of the Laguna district in Mexico. 2 Exami- 
nation of this seed, made by Prof. L. de la Barreda, revealed the fact 
that six lots had been received from infested points in Texas and 
that each of these lots was at that time infested with live boll weevils. 
The results of an examination of samples from three consignments 
arc given in Table XXXII. 

Table XXXII. — Result of examination of infested cottonseed shipped to Mexico. 



Number 
of sacks of 

seed 
examined. 


Boll 
weevils 
found. 


Alive. 


Dead. 


8 
4 
2 


27 
11 

57 


2 
2 
10 


25 
9 
47 


14 


95 


14 


M 



The results of these careful examinations show very clearly the 
possibility of transporting live weevils in shipments of cottonseed. 

Unless the oil mill is within the infested territory and ships hulls to 
points outside there can be very little danger from this product. In 
fact, it is hardly possible that weevils are ever spread by means of 
cottonseed hulls. 

BALED COTTON. 

One of the writers has found live weevils in bagging about bales 
consigned to Liverpool on the wharves at New Orleans. However, 
as has been pointed out, experience has shown that the danger from 
this source is very slight. 

PASSING VEHICLES. 

Carriages, wagons, and railroad trains, in passing fields where the 
weevils are numerous, may carry them great distances, although few 
specific observations have been made on this matter. 

MOVEMENT OF FARM HANDS. 

Many laborers frequently pass from infested territory to uninfested 
territory. Their practice is to use cottonseed for pacKing breakable 
household articles. If the movement takes place late in the season 

i The remainder of this and the next paragraph are from Bull. 51, p. 125. 
2 Boletin de la Comision de la Parasitologia Agricola, vol. 2, pt. 2, pp. 45-58. 



94 THE MEXICAN COTTON-BOLL WEEVIL. 

this cottonseed or sacks used in infested fields may easily be the 
means of spreading the insect. It is thought probable that a sporadic 
infestation at Jackson, Miss., in 1908, originated by such means from 
the heavily infested district around Fayette, Miss. 

UNEXPLAINED SPORADIC OCCURRENCES. 

Infestations at Wichita Falls and Paris, Tex., in 1904, far removed 
from other infestations, can not be explained. A reported infesta- 
tion in 1909 at Temple, Okla., is also of the same nature. 

INTENTIONAL TRANSPORTATION OF THE WEEVIL. 

On several occasions it has been found that the boll weevil has been 
carried into uninfested territory purposely. In some cases the inten- 
tion has been merely to exhibit live specimens and in others to test 
supposed remedies. Whatever the purpose of these introductions 
may be, the practice must be strongly condemned. It is very likely 
to result in the infestation of localities many years in advance of the 
time the weevil would reach them by natural means. The result 
would be a great and unnecessary loss, not only to cotton planters, but 
to merchants and others dependent upon the cotton trade. In this 
connection attention is directed to the fact that a Federal statute pro- 
hibits the interstate shipment of the boll weevil, as well as other 
important insect pests, and prescribes heavy penalties. 1 This act is 
reprinted in part, under the heading "Legal Restrictions," on a sub- 
sequent page. 

In addition to the Federal legislation on this subject practically all 
of the States in the cotton belt have statutes which prohibit the 
importation or having in possession of live boll weevils for any purpose 
whatever. (See the section at the end of this bulletin.) 

HIBERNATION. 2 

There are many popular misconceptions regarding the manner in 
which the boll weevil passes the winter. For this reason we take the 
opportunity to point out some general considerations about hiber- 
nation. 

Many forms of animal life suspend activity during the winter. This 
is the case with the boll weevil and many other insects, as well as 
with certain other animals. During this period of inactivity the 
animals which hibernate derive sufficient nourishment from a supply 
si oied within the body to maintain life. They obtain no other form of 
food. In fact, the hibernation period coincides more or less with the 
periods in which the native food supply is absent. The temperatures 
which kill the cotton plant force the boll weevil into winter quarters, 
where it remains with suspended animation until spring. Almost 
coincident with the first sprout ing of cotton we find the weevils leaving 
their winter quarters and moving about in the fields. 

1 An act. to prohibit importation or interstate transportation of insect pests, etc. (Act of Mar. 3, 1905, 
rli. 1501,33 Stat. L., 1269.) 

2 Two excellent publications on tiie hibernal ion of the boll weevil have been issued. These are: "The 
Hibernation of the Boll Weevil in Centra] Louisiana," by Wilmon Newell and M. s. Dougherty (Cir. 31, 
La. Crop Pest Commission), and "Hibernal ion of the Mexican Cotton-Boll Weevil," by W. E. Hinds and 
W. \V. Yothers (Bui. 77, Bur. Ent., U. S. Dept, Agr.). 



HIBERNATION. 95 

The long absence of the weevils from the cotton fields has led super- 
ficial observers to believe that the weevils pass the egg stage in the 
cotton seed. Such persons point out the fact that the weevils are 
found in seed houses and appear most abundantly in the fields near 
these buildings, and also that they have found insect larvae in the 
seed. As a matter of fact, the insects found in the cotton seed are not 
boll weevils, but other species which feed upon dried seeds and 
similar vegetable matter. The appearance of the early weevils in the 
vicinity of seed houses is due entirely to the fact that the protection 
offered there attracts many in the fall. Careful observations through- 
out the winter have shown that the boll weevil remains inactive except 
for very slight movements during very warm periods and that it does 
not breed in or feed upon cotton seed. 

As explained in another portion of the bulletin, the hibernation 
period is defined by the continuance of mean temperatures within 
what we define as the zone of hibernation. This zone has as its upper 
limit the mean temperature above which, if continued for any con- 
siderable period, the life activities must be resumed, and has for its 
lower limit the absolute temperature below which no weevil can live 
for even a short time. For all practical purposes the hibernation zone 
lies between 56° and 12° F. 

METHODS OF STUDY OF HIBERNATION. 

In studying several features of the hibernation of the boll weevil 
the practice has been to utilize large cages covered with wire screen 
which, were placed in the cotton fields. (See PI. X, b.) No cotton 
was grown in these cages, but at different dates in the fall large num- 
bers of weevils collected in the adjoining cotton were placed in the 
cages. It has been considered that the rate of survival of weevils in 
these cages installed chronologically is an index to the number of 
weevils that actually survive under natural conditions. It has thus 
been considered that with 1 ,000 weevils in a cage installed October 1, 
which showed a survival of 10 per cent, and a cage containing 1,000 
weevils installed on September 15, which showed a survival of 5 
per cent, twice as many weevils would have survived the destruction 
of the plants on October 1 as on September 15. Although there is no 
doubt that this method gives a fairly accurate index, there is one 
objection that can be made to it. This objection is that the number 
of weevils leaving the field to go into hibernation as the season 
progresses, the number dying in the fields, and the number maturing 
there are not taken into consideration as the calculations have been 
made. On September 15 none of the weevils in the field would have 
entered into hibernation. By the 1st of October, however, a certain 
number would have left the field, and such weevils would not be 
represented in the collections made for the cage installed on October 1 . 
It is not known whether the weevils which remain in the fields late 
are more or less hardy than those which leave early to find hibernating 
quarters. The indications, however, are that the stronger and more 
active weevils — that is, those more likely to survive the winter — are the 
ones which do not go into hibernation at an early date. Neverl heless 
the number that may have gone into hibernation between the dates 
of the installation of the various cages, the number that died from 
natural causes, and the number that matured in the fields during that 



96 THE MEXICAN COTTON-BOLL WEEVIL. 

time must be considered. As a matter of fact, the total number of 
weevils in a locality on October 1 would be the number present in the 
cotton fields on September 15, less the total number dying between 
September 15 and October 1, and less the number leaving the field to 
enter into hibernation during that period, plus those that matured 
during the same time. It is likely that the number of weevils matur- 
ing is generally sufficient to offset the number that die from natural 
causes. This leaves only the weevils which escape collection by 
entering into hibernation to be considered. As there is no way in 
which this number can be determined, the method we have followed, 
which ignores them altogether, is the closest approximation we can 
make to a determination of the actual number of weevils which suc- 
ceed in passing the winter after the destruction of the food plants in 
the fall. 

It is to be noted that the possible error in the interpretation of the 
results of hibernation experiments becomes greater in the case of 
the cages installed late in the season. As the season advances more 
and more of the weevils leave the fields and thus pass out of considera- 
tion in connection with the number collected and placed in the cages. 

The hibernation experiments conducted have dealt with 181,932 
weevils utilized in seven different seasons in seven localities through- 
out the infested territory. 

ENTRANCE INTO HIBERNATION. 
SOURCES OF WEEVILS ENTERING HIBERNATION. 1 

Following the maturity of a considerable portion of the crop of 
bolls, and usually in connection with the occurrence of a heavy rain- 
fall, a renewed growth of the plant commonly produces an abundance 
of squares. It is this late top growth of the plant, which serves no 
good purpose so far as further production of cotton is concerned, that 
is primarily responsible in most fields for the needlessly large number 
of weevils produced between the time of maturity of the crop and the 
usual time of destruction of the plants by frost. A large proportion 
of the weevils which become adults before September 1 may be ex- 
pected to die, either as cold weather comes on or during the early 
Eart of the winter season. There is no particular hibernation brood, 
ut representatives of all generations may survive and enter hiberna- 
tion, as has been shown by figure 14 in the discussion of the life cycle. 

STAGES ENTERING HIBERNATION. 2 

The reproductive activity of the weevil continues steadily until 
the plants are destroyed by frost, but it gradually decreases coinci- 
dently with the gradual decrease in temperature. All stages from 
the egg to the adult may be found in both squares and bolls, even 
after frosts have occurred. The immature stages in squares are not 
immediately killed unless the freeze is exceptionally severe, and in 
some localities many of these survive to reach maturity and to 
emerge during the following spring. Usually, however, only those 
which are nearly adult at the time frost occurs may be expected to 

1 The matter in this section is mainly extracted from Bull. 77, Bureau of Entomology, pp. 12, 13. 
8 The matter in this section is largely extracted from Bull. 77, pp. ):',, 14. 



HIBERNATION. 97 

emerge. These might emerge upon warm days following the colder 
weather, but in the absence of a fresh food supply would soon die. 
In the fall of 1903 Prof. E. D. Sanderson, in an examination of 700 
squares at the middle of November, found 79 eggs, which means that 
11 per cent of the squares contained eggs. In an examination of 
1,600 squares he states that 366 larvae were found, showing that about 
23 per cent of the squares contained larvae at the time of entrance 
into hibernation. 1 Some stages may survive in squares for a short 
tune after the freeze, but there are few records of weevils entering 
hibernation as immature stages in squares and surviving to emerge 
therefrom in the spring. These stages are therefore unimportant 
from an economic point of view. 

With immature stages entering hibernation in bolls, the case is 
quite different from that in squares. Very large numbers of weevils 
enter upon the period of hibernation as immature stages and during 
many seasons, especially in the southern part of the State, a large 
percentage of these complete their development, and many survive 
until time for their emergence in the spring. Immature stages in 
bolls have been found alive at Victoria, Tex., as late as February 17. 

TIME OF ENTERING HIBERNATION. 

Hibernation begins when the temperature reaches a point between 
60° and 56° F. The exact point will be higher with a high percentage 
of humidity and lower with a low percentage of humidity. 

According to the observations of Messrs. Newell and Dougherty. 2 
at Mansura, La., in 1908, entrance into hibernation began on October 
28. The mean temperature for 10 days preceding that date was 
63.7° F., but the minimum dropped from 46° to 31° F. on the day the 
weevils began to enter into hibernation. 

The action of the weevils in securing shelter from approaching 
cold is instinctive rather than intelligent. It is probably true that 
they have no such sense of sight as we commonly understand from 
the use of that word and that then selection of shelter is not at all 
guided by that sense. We mean by this that a weevil on a cotton 
plant can not see at any distance shelter which might be attractive 
to it and thereupon fly from the plant to the shelter. Cold nights 
with a temperature between 40° and 50° F., succeeded by warm 
still days, such as occur commonly hi the fall, seem to stimulate the 
weevils to an unusual activity both in flight and in crawling. It 
seems possible that they have an instinctive knowledge of the approach 
of temperature conditions from which they must secure shelter, but 
it is also true that many weevils remain active upon plants for some 
time after the plants have been destroyed by frost and frequently 
until several weeks after other individuals have entered hibernation. 
In speaking of entering hibernation, therefore, we mean the entrance 
of the weevils upon a period of comparative if not complete inactivity. 
Their action in securing shelter is gradual and governed primarily 
by the degree of protection from the cold which they may receive. 
If early in the season a weevil accidentally finds shelter which gives 
it exceptional protection from the cold it will likewise be exception- 
ally protected from heat and therefore less likely than are other less 

1 Bull. 63, Bureau of Entomology, U. S. Dept. of Agriculture. 
a Cir. 31, Lousiana Crop Pest Commission, p. 170. 

28873°— S. Doc. 305, 62-2 7 



98 



THE MEXICAN COTTON-BOLL WEEVIL. 



fortunate individuals to resume its activity upon warm days. If 
at first the shelter which weevils find is only slight they will be easily 
influenced by succeeding warmth, and in another period of activity 
will be likely to find better protection. Their flight upon warm days 
undoubtedly leaves large numbers of them outside of the cotton 
fields, where they are more likely to find favorable shelter than within 
the fields themselves. 

From this explanation it will be understood that it is rarely pos- 
sible to indicate by a single date the time when weevils enter hiber- 
nation. It may be better expressed as a period within the limits of 
which a large majority, though possibly not all, weevils may seek 
shelter. Naturally this time varies according to the seasonal tem- 
perature conditions, so that in a certain locality it may occur several 
weeks earlier in one season than in another. It is also evident that 
differences in temperature conditions due to latitude or altitude will 
cause a similar variation in the time when weevils enter hibernation. 1 

In Table XXXIII are shown the times of the year in which the weevils 
entered hibernation in the experiments of 1903 to 1906, together with 
the temperature conditions prevailing. The table shows the relation- 
ships between humidity and temperature and the length of the period 
of entrance into hibernation. In short, it may be stated that the 
lower the mean temperature the shorter the period of entrance. 
Sufficient information is not at hand to show positively the influence 
of humidity, but it is evident that there is a decided influence. 



Table XXXIII.— Period 


of entrance of the boll weevil irito hibernation and meteoro- 
logical conditions. 


Year. 


Locality. 


Period. 


Mean 
tempera- 
ture. 


Mean 


Limits. 


Days. 


humidity. 


1905 


Dallas, Tex 


Nov. 29-Dec. 8 

Nov. 15-27 


10 
13 
16 
19 
26 
27 
28 
43 


"F. 
40.5 
49.5 
53.0 
50.0 
55.0 
53.0 
57.5 
60.4 


Per cent. 
64 8 


1903 


College Station, Tex 




1903 


Victoria, Tex 


Nov. 15-30 




1905 


do 


Nov. 30-Dec. 18 

Nov. 10-Dec. 5 

Nov. 12-Dec. 8 

Nov. 11-Dec. 8 

Nov. 9-Dec. 21 




1904 


Corsicana, Tex 




1906 


Dallas, Tex 


73 1 


1904 




79 3 


1906 


do 











Weevils can not be forced to hibernate when conditions do not nor- 
mally induce hibernation. If kept without food, they will starve. 
The real bearing of this statement will be brought out later in con- 
nection with the summaries of the survival in its relation to the 
time of beginning hibernation. (See Table XL VI.) 

NUMBER OF ADULT WEEVILS ENTERING HIBERNATION. 



Of course the number of adult weevils entering hibernation is a 
variable quantity, owing to the differences in the percentage of infes- 
tation in various regions and seasons. Examinations m heavily 
infested regions have shown averages as high as 58,000 adult weevils 



1 This and the preceding paragraph are remodeled from Bull. No. 77, Bureau of Entomology. 



HIBERNATION. 



99 



per acre in the middle of November. In this connection it is inter- 
esting to note the progress of entrance into hibernation as shown by 
Table XXXIV, based on investigations made at Dallas in fields 
with an average of 8,300 plants per acre. 

Table XXXIV. — Number of boll -weevils per acre upon stalks at different dates at 

Dallas, Tex. 1 



Date. 


Plants 
exam- 
ined. 


Living 
weevils 
found. 


Living 
weevils 
per acre. 


1906. 
Oct. 12 


110 
S4 
60 
35 
35 
36 
35 

35 


122 
190 
106 
29 
27 
10 
5 

3 


9,205 
18,774 
14,663 
6,877 
6, 403 
2,306 
1,186 

711 


Nov. 10 


Nov. 20 


Nov. 22 


Dec. 1 


Dec. 18 


1907. 
Jan. 21 





1 From Bull. 77, Bureau of Entomology, p. 18. 



In connection with this subject we include also Table XXXV for 
the same period, showing the occurrence of the weevils under shelter 
on the ground in the cotton fields. 

Table XXXV. — Number of weevils under rubbish on ground at Dallas, Tex. 2 



Field. 


Date ex- 
amined. 


Portion 

of acre 

examined. 


Weevils 
found- 


Total 
per acre. 


Percent- 
age 

alive. 


Remarks. 




Alive. 


Dead. 




A 


1906. 
Nov. 15 

...do 


22 plants. 

1/264 
1/347 
1/264 

10/8384 
10/6236 
10/8384 


4 

4 

8 
5 

5 

1 
2 






14 

2 
1 
2 


1,450 

1,056 
2,776 
5,016 

6,870 

1,247 
3,354 


100.0 

100.0 
100.0 
26.3 

71.4 
50.0 
50.0 


In cracks of ground around bases 


A 


of plants. 
Under rubbish on ground. 


A 


Nov. 22 
Dec. 18 

1907. 
Jan. 11 
Jan. 29 
...do 


Do. 


A 


Do. 


B 


Northeast corner of field. 


c 


Middle of field. 


c 


Near southwestern edge. 









2 This table and the following paragraph are taken from Bull. 77, Bureau of Entomology, p. 20. 

The sum total of weevils found both on plants and on the ground 
on November 22 shows an average of slightly more than 9,000 weevils 
per acre, all of which were alive. On December 18 the number that 
could be accounted for was between 6,000 and 7,000 per acre on the 
same ground which had been previously examined. On the former 
date more than two-thirds of the weevils were still upon the plants. 
On the latter date nearly five-sixths of them were on the ground, and 
among those on the ground only 26 per cent were living. These fig- 
ures show that between November 22 and December 18 a very large 
mortality had occurred among weevils which had entered hiberna- 
tion, and especially among those which had sought shelter under rub- 
bish upon the surface of the black-waxy soil of field A. 



100 THE MEXICAN COTTON-BOLL WEEVIL. 

SHELTER DURING HIBERNATION. 

Boll weevils in seeking shelter from the cold will enter all kinds 
of places which might afford shelter. The following statements are 
quoted from Prof. E. D. Sanderson: J 

The observations by Prof. Conradi at College Station, Tex., in the early winter of 
1903, probably indicate some of the normal places for hibernation — that is, under 
dead leaves, in old cotton brush, and under loose bark. In the hibernation cages, 
where the weevils were furnished an abundance of rubbish, it was found that many 
of them which were hibernating successfully had crawled into the cavities made by 
borers in dead wood and in similar positions where they were well protected. It has 
been often noticed that in a wooded country the weevils appear first in spring along 
the borders of fields next to the woods and gradually work inward from the edges, so 
that it seems probable that in a wooded country most of them hibernate in woodland. 
Around outbuildings and barns also are found favorable places, as there is always 
more or less rubbish and protection in such situations. In 1903 more than five times 
as many weevils were found in a piece of cotton near the college barn, where cotton 
had been grown the previous year, than were found in any other locality in that 
neighborhood. It is also noticeable that weevils are always more numerous near gins 
than at a distance from them. 

It is noticeable that weevils are much more abundant where cotton is planted in 
fields where sorghum stubble has been allowed to remain all winter adjoining a last 
year's cotton field. 

Professor Mally has given the observations of Mr. Teltschick upon finding weevils 
hibernating in the crevices of the soil around the cotton stalks and roots, at a depth 
of 3 inches. On March 7, 1901, a raw, windy day, upon 35 stalks, he found 7 live 
and 2 dead weevils from 1 to 3 inches below the surface. In September, 1902, he stated 
that he had again found weevils in a similar situation during the previous spring, but 
not as many of them as in 1901. Mr. Teltschick recently writes as follows: 

''I found but few weevils in crevices around stalks during the last two winters, 
partly because there were no crevices (frequent rains filling them up as soon as formed) 
and partly because freezes were severe enough to keep cotton from coming out during 
any part of the last two winters; whereas in 1900 we had neither rain enough to fill up 
crevices nor frost enough to keep cotton from budding out at intervals at the base of 
the stalk, which latter fact accounts, no doubt, for the relatively large number of 
weevils found within the crevices." 

Where the cotton stalks are allowed to stand throughout the 
winter they furnish the weevils both the means of subsistence late 
in the fall and an abundance of favorable hibernation places through- 
out the field. The prospects of successful hibernation are thereby 
multiplied many times, and, furthermore, the weevils are already 
distributed over the field when they first become active in the spring. 
The grass and weeds which almost invariably abound along fence 
fines are exceedingly favorable to the hibernation of many weevils, 
so that it will be found generally true that the worst line of infesta- 
tion in the spring proceeds from the outer edges of the field inward. 
Where cotton and corn are grown in adjacent fields, or where, as is 
sometimes the case, the two are more or less mixed in the same field, 
many weevils find favorable shelter in the husks and stalks of the 
corn. An especially favored place is said by Mr. E. A. Schwarz to 
be in the longitudinal groove in the stalk and within the shelter of 
the clasping base of the leaf. Perhaps the most favorable of all 
hibernating conditions are to be found among the leaves and rubbish 
abounding in the edges of timber adjoining cotton fields and in 
Spanish moss. From such sources the weevils are known to come 
in large numbers in the spring. Sorghum stubble, which collects 
debris blown about by the wind, is also very favorable for hibernation. 



i Bull. 63, Bureau of Entomology, U. S. Dept. Agriculture, pp. 18-19. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XII 




Fig. a. — Standing dead timber and forest environment favorable for hibernation of weevils. 

(Original. ) 




Fig. b. — Litter in forest, suitable for hibernation of weevils, i ( iriginal.) 
Hibernation Conditions for the Boll Weevil. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XIII. 




I > 




90 



■>■ 



HIBEENATION. 101 

Attention has already been called to the fact that many stages 
enter the period of liibernation in an immature condition in unopened 
bolls. That adult weevils hibernate entirely within the protection 
afforded by the bracts and hulls of bolls has been abundantly demon- 
strated. Messrs. Hinds and Yothers x showed, however, that the 
percentage of live stages in bolls decreased rapidly during the winter, 
thus proving that the bolls do not furnish perfect hibernation shelter. 
Their results may be summarized as follows: 

Table XXXVI. — Seasonal decrease of live stages of the boll weevil in bolls; percentage 
of bolls containing live stages. 

December 30. 00 

January 1. 15 

February 0. 29 

March 0. 00 

As would be expected, it was found that there was a greater per- 
centage of survival in bolls in southern localities. 

During an ordinary season it can not be doubted that a large 
majority of the weevils which survive find some other shelter than 
the bolls hanging upon the plants. It is not, however, as easy a 
matter to find weevils in rubbish scattered upon the ground as in 
bolls. It is necessary to collect the rubbish very carefully and sift 
it over cloth or paper to separate the weevils from the trash. In 
this way it has been found that weevils hibernate extensively in the 
leaf and grass rubbish distributed throughout the field. Naturally, 
the cleaner the field in the fall the smaller will be their chances of 
finding favorable shelter during the winter. 2 (PI. XII, b.) 

Standing trees are a common sight in cotton fields, and while the 
records of weevils found hibernating under bark are but few, they 
are sufficient to indicate that these trees may be rather important 
factors where they occur in considerable numbers. (PI. XII, a.) 

Where the Spanish moss (Tillandsia usneoides) occurs, as in the 
bottom lands in the coast section of Texas and in the southern por- 
tions of the Gulf States generally, weevils find exceptionally favor- 
able shelter. Many examinations of large quantities of moss have 
been made to ascertain the importance of this form of shelter. The 
maximum number of weevils per ton of moss is recorded by Messrs. 
Newell and Dougherty (1909) as 3,158 in moss collected from an 
elm tree located in a swamp at Mansura, La., December 23, 1908. 
The moss was at a height or 15 feet. The tree was one-fourth of a 
mile from the nearest cotton field. On January 9, 1910, Mr. C. E. 
Hood found at Mansura 924 boll weevils and 2,156 boll- weevil para- 
sites per ton of moss collected at from 1 to 8 feet above the ground. 
The weevils seem to prefer the festoons of green-hanging moss to 
the dead masses. (See Pis. XI, XIII.) 

Cornfields adjoining cotton, or cornstalks scattered throughout 
cotton fields may shelter many weevils. This was first noticed by 
Mr. E. A. Schwarz at Victoria, Tex., in the winter of 1901-2, and 
has since been corroborated by a number of observers. Several 
examinations have been made of haystacks in the vicinity of cotton. 

1 Bull. 77, Bureau of Entomology. 

* This paragraph and the remainder of the discussion in the present section is modified from Bull. 77, 
Bureau of Entomology, pp. 30-33, 41, 42. 



102 THE MEXICAN COTTON-BOLL WEEVIL. 

This is a task quite comparable with that of seeking for the pro- 
verbial needle, and it is not surprising that the results have been 
very meager. The fact, however, that traces of weevils have been 
found in these examinations indicates that weevils may find shelter 
under such conditions. 

Farmyards, seed houses, barns, ginneries, and oil mills also afford 
favorable shelter for weevils. Especially in ginneries and seed 
houses the weevils become concentrated with the cotton or seed and 
frequently may be found in large numbers within or around these 
buildings. In connection with this subject the reader is referred to 
a fuller discussion of the significance of ginneries and oil mills in the 
distribution of weevils and of the methods recommended for con- 
trolling them. 1 

In order to have a basis of comparison of the various kinds of 
shelter, many cage experiments have been conducted. In Table 
XXXVII will be found a comparison of the survival in the cages at 
Keatchie, La., for weevils installed November 23 and 29. 

Table XXXVII. — Favorable conditions for hibernation determined by rank in per- 
centage of weevils surviving at Keatchie, La., in 1905-6. l 



Nature of shelter. 



Weevils 
put in. 



Weevils survived. 



Number. Percent 



Ordinary field stalks, grass, etc 

Brush, leaves, stumps, logs; stalks standing 

Same as above, but stalks removed 

Cotton seed, piled but uncovered; stalks standing. 

Absolutely bare ground 

Cotton seed piled and covered; stalks left standing 



2,000 
2,500 
3,300 
2,000 
2,000 
2,000 



4.65 
3.56 
2.12 
1.50 
1.50 
1.15 



1 From Bull. 77, Bureau of Entomology, p. 42. 

It is evident from these observations that ordinary field conditions 
where stalks are allowed to stand together with the grass and leaves 
littered over the ground are as favorable as any other for successful 
hibernation. One fact should be emphasized in regard to classes of 
shelter which have been mentioned as occurring within cotton fields, 
i. e., that it is possible, as a rule, to destroy or remove practically all 
of them. Undoubtedly the burning of cotton stalks, weeds, grass, 
and other rubbish is the easiest and most effective method of destruc- 
tion where it can be practiced. Next to this in importance would 
be the destruction of the stalks by a stalk chopper and plowing under 
all the rubbish. In the latter case it must be stated that many weevils 
which, under dry conditions, are buried not more than 2 inches will be 
able to escape through the soil and may then find shelter near, if not 
within, the field. 

i Farmers' Bull. 209, U. S. Dept. of Agriculture, "Controlling the Cotton Boll Weevil in Cotton Seed and 
at Ginneries." 



HIBERNATION. 



103 



ACTIVITY DURING THE HIBERNATION PERIOD. 

It is natural to expect that during warm periods of winter the tem- 
perature will rise to a point which forces the weevils into activity., 
Of course, the weevils under the lightest shelter are the ones which 
first become active. It is these warm periods which cause the inter- 
mittent development of the immature stages in dry bolls left in the 
fields. In some winters the hibernation is incomplete throughout 
the cotton belt, and in the extreme South it is probably so almost 
every winter. This same temperature condition is responsible for 
the growth of sprout cotton, which affords food in the warm periods. 
Observations were made in January, 1907, on weevils feeding on 
sprout cotton at Victoria, Tex., at a mean temperature of 67° F. 

DURATION OF HIBERNATION PERIOD. 



AVERAGE LENGTH OF HIBERNATION PERIOD. 

Many factors must be considered in arriving at the average length 
of the hibernation period. The time of entrance, condition of the 
weevils on entering, temperature and humidity before and during 
hibernation, and nature of shelter, all have a decided effect upon the 
duration of hibernation. In a series of condensed summaries we 
have attempted to show how some of these factors act. 

In Table XXXVIII is to be found a general summary of the nine 
large experiments conducted, with the extreme variations in each 
series. From this table it appears that in the years 1906 to 1911 the 
hibernation period has ranged between 62 and 255 days, and that in 
1909 the range fell short only 1 day of this maximum range. It 
also appears that the average duration in Texas is 26 days shorter 
than in Louisiana. The period of emergence extends from Feb- 
ruary 15 to July 1. 

Table XXXVIII. — Extremes of variation in duration of hibernation by the boll weevil. 



Place. 


Total 
number 
weevils 
emerged. 


Total 

number 
weevil 
days. 


Mini- 
mum 
period. 


Maxi- 
mum 
period. 


Mini- 
mum 
aver- 
age. 


Maxi- 
mum 
aver- 
age. 


Aver- 
age of 
aver- 
ages. 


Earliest 
emergence. 


Latest 
emer- 
gence. 


Keatchie, La., 1906 

Mansura, La., 1909 
Mansura, La., 1910... 
Tallulah, La.,1910 
Tallulah, La., 1911 


731 
3,260 
1,038 

317 
46 


114,192 
516,067 
170,212 
58. 245 
6,587 


Days. 
108 
62 
86 
103 
107 


Days. 
222 
254 
232 
237 
231 


Days. 
136 
94 

114 
126 
118 


Days. 
178 
199 
217 
224 
158 


Dai/s. 
156 
156 
164 
183 
143 


February 21. 
February 15. 
February 15. 

February 15. 

February 15. 

February 28. 

March 4 

March 1 

March 2 

February 28. 

February 15. 


June 28. 
June 29. 
June 15. 
June 27. 
June 4. 


Louisiana aver- 


5,392 


865,303 


62 


254 


94 


224 


160 


June 29. 






Victoria, Tex., 1907.... 
Calvert, Tex., 1907 
Dallas, Tex., 1907 
Dallas, Tex., 1908 


3,028 

1,842 

3,462 

118 


383, 797 

255.831 

481, 271 

17,839 


92 
91 
85 
113 


223 
255 
233 
217 


95 
100 

98 
121 


146 
195 
168 
170 


126 
138 
138 
151 


June 15. 
July 1. 
June 19. 
June 16. 


Texas average . . . 


8,450 


1,138,738 


91 


255 


98 


195 


134 


July 1. 


Grand total 


13,842 


2,004,041 


62 


255 


94 


224 


144 


Julyl. 



104 



THE MEXICAN COTTON-BOLL WEEVIL. 



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HIBERNATION. 



105 



Knowing that the time of entrance affects the percentage of sur- 
vival, it is also reasonable to expect an effect upon the duration of the 
hibernation period. Table XXXIX has been constructed to show 
the average duration and average date of emergence at each locality 
for all weevils entering hibernation in each half month during the 
several seasons of the experiments. It will be noted that the length 
of the period, with a few minor exceptions, decreases in accordance 
with the lateness of entrance. It is very strikingly shown that in any 
given period of entrance the duration in Texas is considerably shorter 
than in Louisiana. On the other hand, it is impossible to show from 
this table any progression in the average date of emergence. 

The diagram (fig. 22) shows graphically the correspondence between 
date of installation and period of hibernation and emphasizes the 
differences between Texas and Louisiana. 



RELATION OF SHELTER TO DURATION OF HIBERNATION. 

That the nature of the hibernating quarters has a direct bearing 
upon the duration of the period is to be gathered from the records of 
Messrs. Newell and Dougherty made at Mansura, La., in 1909, which 
are abstracted below: 

Table XL. — Comparison of length of hibernation of the boll weevil in different shelters 
at Mansura, La., 1909. 1 



Date started 19Q8. 


Nature of 

hibernation 

quarters. 


Location of 
cage. 


Number 

of 
weevils 

con- 
tained. 


Number 

of 
weevils 

surviving 
winter. 


Average 
number 
of days 
in hiber- 
nation. 


Average 
date of 
emer- 
gence. 


October 2f> 


Average... 
do 


In open field.. 
In swamp 
In open field.. 
In swamp 


1,294 

1,142 

1,214 

938 


325 
162 
409 
408 


169.1 
173.3 
190.9 
199.4 


April 13 
April 17 
May 4 
May 13 


Do : 


Do 

Do 


Moss 

.do .. 






Total 


4,588 


1,304 






Average 






185.0 


April 28 













i This table and the following statements are extracted from Cir. 31, State Crop Pest Commission of 
Louisiana. 

Consideration of Table XL reveals the interesting fact that weevils 
hibernating in the cool, shaded situations in timber remained in hi- 
bernation an average of about seven days longer than those 
hibernating in the open field. Weevils which hibernated in moss in 
the swamp remained in hibernation practically 200 days, and those 
winch passed the winter in moss on trees in the open field remained in 
hibernation 191 days. In marked contrast to this the weevils that 
hibernated in a general assortment of materials in the open field 
remained in hibernation only 169 days, though gathered from the 
cotton fields at exactly the same date in the fall of 1908. This proves 
the dangerous nature of the moss, for it really causes the weevils in it 
to remain in hibernation for nearly a month longer than they would 
if hibernating in other materials. 

Table XL also illustrates the influence of temperature upon the dura- 
tion of the hibernation period, for there is no doubt that it is the temper- 



106 



THE MEXICAN" COTTON-BOLL WEEVIL. 



ature prevailing in the exact spot where the individual weevils are hiber- 
nating that determines the date of emergence from hibernation. Piles 
of grass in the open field are warmed by the sun in February and March, 
and the weevils emerge from them at that time. The shaded places 
of the forest or swamp are cool and damp, and they do not reach an 



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Fig. 22.— Diagram illustrating average length of hibernation period of the boll weevil as related to date 
of entering hibernation. (Original.) 

equivalent temperature until some weeks afterwards, and the wee- 
vils consequently emerge later in such places than in the open fields. 
The bunches of moss are so resistant to heat that even in the hottest 
days of summer they are very noticeably cooler than the air. 

EMERGENCE FROM HIBERNATION. 



TIME OF EMERGENCE. 



The time of emergence of the boll weevil from hibernation ranges 
from February 15 to July 1. It is necessary to discuss the conditions 
which cause tins irregularity. A careful study of all the series of 
experiments to determine the immediate causes for the first decided 
impulse to emerge has resulted in the following conclusion : That the 



HIBERNATION. 



107 



time of emergence varies with the total effective temperature and 
the rainfall. Computing the total effective temperature from Jan- 
uary 1 in daily units of mean temperature above the mean of 56° F. 
(average zero of effective temperature) it is found that approximately 
172.6° F. of effective temperature and 5.1 inches of rain are necessary to 
bring the weevils out of hibernation in comparatively large numbers. 
If the rainfall is greater than 5.1 inches the necessary effective 



S 6 7 




9S* 



/20» /45° /70° /95° 220° 245" 



295" 



Fig. 23. 



-Diagram illustrating relations of effective temperature and precipitation to date of beginning 
emergence of the boll weevil. (Original.) 



temperature usually will be less than 172.6° F., and, on the other hand, 
if the total effective temperature is greater than 172.6° F. the necessary 
rainfall will usually be less than 5.1 inches. This may be seen by 
reference to Table XLI and by the diagram (fig. 23). Dis- 
crepancies wdl occur with regard to this formula and will in a large 
measure be due to the type of shelter or to great irregularities in the 
climate. 

Table XLI. — Relation of effective temperature and precipitation to date of beginning 
emergence of the boll weevil. 



Place. 



Tallulah.,1910 
Mansura, 1910 
Dallas, 1908... 
Dallas, 1907... 
Mansura, 1909 
Victoria, 1907. 
Calvert, 1907.. 



Total 
effective 
tempera- 
ture from 

Jan. 1. 



F. 
65 
115 
160 
170 
185.5 
260 
303.7 



Total 
precipita- 
tion from 

Jan. 1. 



Inches. 

10.5 
7.3 
6.5 
2.2 
5.5 
1.3 
2.35 



Date of 

first 

extensive 

emergence. 



March 1. 
March 2. 
March 12. 
March 3. 
February 21. 
February 23. 
March 5. 



108 



THE MEXICAN COTTON-BOLL WEEVIL. 



Figure 23 shows graphically that climate influences the time of 
beginning emergence. It also has a decided effect upon the sub- 
sequent emergence. In Table XLII is shown what effect the daily 
mean temperature has upon the hibernating weevil. 



Table XLII. 



■The relation of emergence of the boll weevil to increase in temperature at 
Keatchie, La., and Dallas, Tex., 1906. ' 





Keatchie, La. 


Dallas 


, Tex. 


Total 
number 

of 
weevils 
emerged. 


Per cent 

based on 

grand 

total 

emerged. 


Range of temperatures (° F.). 


Number 

of 
weevils 
emerg- 
ing. 


Per cent 
of total 
emer- 
gence. 


Number 

of 
weevils 
emerg- 
ing. 


Per cent 
of total 
emer- 
gence. 


43-57 


20 
52 
116 
127 
309 
84 
20 


2.7 
7.1 
16.0 
17.5 
42.4 
11.5 
2.7 



2 
25 
18 
10 






3.6 
45.5 
32.7 
18.2 






20 
54 
141 
145 
319 
84 
20 


2.5 


58-63 


6.8 


64-08 


17.8 


69-73 


18.5 


74-78 


40.7 


79-83 


10.7 


84-93 . . 


2.5 






Total 


728 


100.0 


55 


100.0 


783 


100.0 







1 Modified from Bull. 77, Bureau of Entomology, p. 44. 

The number of weevils emerging under 57° F. is very small indeed. 
From that point the emergence increases with the increase in tem- 
perature until a majority of the weevils have emerged. Most 
weevils have been found to leave their winter quarters during a 
temperature averaging between 64° and 78° F. At Keatchie 75 

Eer cent and at Dallas 96 per cent of the total emergence took place 
etween these limits. At Dallas the largest emergence occurred 
between temperatures of 64° and 68° F., while at Keatchie the 
largest emergence occurred between 74° and 78° F. In a preced- 
ing paragraph we have shown that higher temperatures are neces- 
sary to affect the weevils hibernating in Louisiana, apparently 
because of the heavier shelter. 



RATE OF EMERGENCE. 

With a long-continued emergence period it is important to deter- 
mine whether the rate of emergence is equal at all times or has its 
periods of retardation and acceleration. Upon charting the per- 
centage of total emergence for each week it was noted that the 
Texas and Louisiana points differed considerably. On the accom- 
panying diagram (fig. 24) the four Texas series are consolidated to 
give the average rate, and likewise the four Louisiana series are 
consolidated, while in Table XLIII the records for each locality are 
given. It is immediately apparent that the emergence begins much 



HIBERNATION. 



109 



more abruptly in Texas than in Louisiana. In Texas 25 per cent 
have emerged by March 12, 50 per cent by March 21, 75 per cent by 
April 8, and 100 per cent not until June 19. On the other hand, in 
Louisiana 25 per cent have not emerged until March 30, 50 per cent until 
April 27, 75 per cent until May 16, while 100 per cent will have emerged 
only by July 3. Herein lies a powerful argument for early planting. 
With 50 per cent of the weevils emerging after March 21 in Texas 



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Fig. 24.— Diagram illustrating average rate of emergence of the boll weevil from hibernation in Texas 

and Louisiana. (Original.) 



and 86 per cent emerging after the same date in Louisiana, or with 
75 per cent emerging after April 8 in Texas and 64 per cent yet to 
emerge after the same date in Louisiana, it becomes evident that 
every day gained hi Texas before March 21 or in Louisiana before 
April 8 is of immense importance in the fight against the weevil. 
Even later than these dates every day counts a great deal, because 
it is apparent that the longer planting is deferred the more weevils 
will be out to attack the cotton when it comes up. 



110 THE MEXICAN COTTON-BOLL, WEEVIL. 

Table XLIII. — Percentage of total emergence of the boll weevil out at given dates. 



Date. 



Keatchie, 


Tallulah, 


Mansura, 


Mansura, 


Dallas, 


Calvert, 


Dallas, 


Victoria, 


La., 


La., 


La., 


La., 


Tex., 


Tex., 


Tex., 


Tex., 


1906. 


1910. 


1910. 


1909. 


1908. 


1907. 


1907. 


1907. 


0.00 


0.31 


1.64 


7.20 


0.00 


0.00 


0.00 


0.00 


.00 


.31 


3.28 


10.61 


.00 


.00 


.00 


12.01 


.00 


6.62 


10.56 


19.22 


7.27 


22.80 


24.48 


27.92 


.00 


10.09 


15.69 


19.73 


23.63 


31.90 


36.36 


48.23 


.00 


13.56 


21.19 


23.24 


45.45 


44.30 


57.14 


66.24 


3.93 


23.34 


38.05 


30.95 


55.45 


57.20 


71.72 


79.35 


6.87 


35.95 


46.53 


38.16 


63.63 


64.20 


75.70 


84.16 


24.54 


41.95 


49.42 


43.87 


68.18 


70.40 


81.28 


89.58 


32.11 


46.05 


52.41 


47.78 


74.54 


77.70 


84.46 


93.80 


40.67 


48.89 


53.86 


56.39 


87.27 


79.51 


85.74 


95.02 


52.73 


61.83 


60.41 


61.30 


90.91 


82. 62 


88. 62 


95.88 


60.44 


70.66 


72.35 


67.51 


91.82 


88.73 


92.30 


97.50 


72.22 


75.39 


75.64 


75.12 


94.55 


91.94 


95.78 


98.36 


86.41 


88.64 


84.77 


82.43 


98.18 


94.95 


98.76 


98.92 


91.60 


93.69 


92.77 


89.73 


98.18 


97.56 


99.34 


99.18 


97.36 


99.05 


98.43 


96.83 


99.09 


99.17 


99.73 


99.90 


99.19 


99.68 


99.89 


97.83 


99.09 


99.68 


99.88 


99.97 


99.61 


99.68 


100. 00 


98.74 


100. 00 


99.99 


100. 00 


100. 00 


99.89 


100. 00 


100. 00 


99.94 


100.00 


100.00 


100. 00 


100.00 


100. 00 


100.00 


100. 00 


100. 00 


100.00 


100. 00 


100. 00 


100.00 



Tallulah, 
La., 
1911. 



February 21 
February 2S 

March 7 

March 14. . . 
March 21 . . . 
March 28... 

April 4' 

April 11 

April 18 

April 25 

May 2 

May 9 

May 16 

May 23 

May 30 

June 6 

June 13 

June 20 

June 27 

July 4 



36.95 
30.95 
39.92 
63.83 
70.35 
72.52 
74.69 
81.21 
87.73 
96.42 
96.42 
98.59 
98.59 
98.59 
98.59 
100.00 
100.00 
100.00 
100.00 
100.00 



The nature of the shelter in which the weevils are hibernating has a 
decided influence upon the rate of emergence, as is shown in Table 
XLIV, based upon the experiments of the Louisiana Crop Pest 
Commission at Mansura, La., in 1909. 



Table XLIV.- 



-Effect of nature of shelter upon rate of emergence of the boll weevil, at 
Mansura, La., 1909. 



Character of hibernating quarters. 



Average quarters (cag^s 5 and 51 ) 

Open field (cages A a d 5) 

Swamp (cages Band 51) 

Moss (cages A and B) 



Dates by which certain percentages of the 
surviving weevils were out of hibernation. 



25 per cent. 



March 19. 
March 31. 
April 8... 
April 13.. 



50 per cent. 



April 12. 
April 29. 
Mav 20. . 
...do... 



75 per cent. 



May 15. . . 
May 24. . . 
June 1 . . . 
June 2. . . 



100 per 
cent. 



June 27. 

June 21. 

June 29. 

Do. 



It will be noticed that only four cages entered the consideration, 
cage 5 being average quarters in open field, cage 51 being in average 
quarters in swamp, cage A being Spanish moss in open field, and cage 
B being moss in swamp. 

SURVIVAL OF HIBERNATED WEEVILS. 

The central idea in all the hibernation experiments has been the 
determination of the percentages of weevils which survive under 
different conditions and different treatments. In obtaining the facts 
which have been discussed in the preceding and following paragraphs 
on hibernation the grand total of 181,932 weevils has been used. 
With such a large series it is reasonable to suppose that the average 
percentage of survival must veiy nearly approximate the normal. 
This survival in nine series of experiments conducted in seven years 
at six localities representing the principal climatic, shelter, and other 
conditions of the infested region has been 7.6 per cent. Table XLV 
presents the final summaries of each ot the nine series. 



HIBERNATION. 



Ill 



Table XLV.- 



-Summary of survival of the boll iveevil in all the more important 
experiments. 



Places. 



Keatchic, La.. 1900.. 
Mansura, La., 1909. . 
Mansitra, La., 1910. . 
Tallulah, La., 1910... 
Tallulah, La.. 1911.. 
Live Louisiana series 
Dallas, Tex., 1907.... 
Calvert, Tex., 1907... 
Victoria. Tex., 1907.. 
Dallas, Tex., 1908... 

Four Texas series 

Total of nine series. . . 



Total 
number of 
weevils 
entering 
hiber- 
nation. 



24,700 
16, 281 
22, 179 

21,s:if, 
8,439 
93, 331 
32, 439 
20, 430 
23,645 
12, 087 
88, 601 
1S1.932 



Total 

number of 
weevils 

surviving 
hiber- 
nation. 



731 
3,260 

l.nux 

317 

•If, 

5,392 

3,464 

l.s:;.| 

3.020 

118 

8,442 

13, 834 



Percent- 
age of 

survival. 



2.1 
20.0 

4.6 

1.4 
.5 

5.7 
10.6 

8.9 

12.8 

.9 

9.5 

7.6 



The highest average percentage of survival for any locality is 20 
per cent, at Mansura, La., in 1909, and the lowest average is 0.5 per 
cent, at Tallulah, La., in 1911. The highest percentage of survival 
in any cage was 47.72 per cent of 767 weevils, at Mansura, in a cage 
with average conditions established December 14, 1908. The lowest 
percentage of survival is no weevils, from 408, at Tallulah, in two 
cages with average conditions, established November 15, 1910. 



RELATION OF FALL DESTRUCTION TO SURVIVAL. 

One of the most important recommendations for boll-weevil con- 
trol is that of early destruction of the cotton stalks. It has long been 
known that the earlier the stalks are destroyed the less chance the 
weevils have of surviving. Table XLVI, showing the percentage of 
emergence by dates of installation, affords an incontrovertible argu- 
ment in support of this recommendation. 

Table XLVI. — Percentage of emergence of the boll weevil, by dates of installation. 



Place. 


Sept. 16- 
30. 


Oct. 1- 
15. 


Oct. 16- 
31. 


Nov. 1- 
15. 


Nov. 16- 
30. 


Dec. 1- 

15. 


Dec. 16- 
31. 


Texas points. 
Dallas, 1907 


Per cent. 


Per cent. 
2.61 
3.15 


Per cent. 
6.67 
3.98 
6.17 

2.8 


Per cent. 
20.57 
10.33 
17.69 
1.68 


Per cent. 
4.36 
2.65 
16.22 
5.26 


Pet tail. 


Per crnt. 


Calvert, 1907 








Victoria, 1907 








Dallas, 1908 


0.23 


.39 












Texas, weighted average 
percentage 


.23 


2.33 


5.62 


15.42 


16.05 












Total weevils installed 


5,213 


7,729 


27,806 


30, 431 


12,173 












Louisiana points. 
Keatchic, 1900 










2.71 
24.56 
6.31 
2.4 


3. 23 

43. 23 
6.79 

.00 
.00 




Mansura, 1909 


2.7 
.23 
.34 


3.31 
1.31 
2.23 

1.15 


23.9 
6.58 
1.16 
.54 


23.8 

9.95 

1.53 

.00 


37.06 


Mansura, 1910 


Tallulah, 1910 




Tallulah, 1911 












Louisiana, weighted aver- 
age percentage. . < 


.37 


2.00 


8.04 


8.S2 


6.07 


10.65 


12.61 




Total weevils installed 


8,186 


14,21S 


24, 464 


9,620 


24,252 


10, 208 


1,483 




Grand weighted average 
perceniage 


0.31 


2.07 


6.58 


14.20 


9.00 


. 10.65 


12.61 




Total weevils installed 


13, 399 


21,947 


52,270 


40,051 


36,425 


10,208 


1,483 



112 



THE MEXICAN COTTON-BOLL WEEVIL. 



Converted into terms of the number of weevils in every thousand 
which would survive the winter if stalks were destroyed on a given 
date, we can see the force of Table XLVL It is even more evident 
from the arrangement of the data given below in Table XLVII. 

Table XLVII. — Number of boll weevils in each 1,000 which would have survived 
destruction of stalks on a given date. 



Date of destruction. 



In Loui- 
siana. 



September 16-30 

October 1-15 

October 1(5-31... 
November 1-15.. 
November 16-30. 
December 1-15. . 
December 16-31. 




RELATION OF SHELTER TO SURVIVAL. 



It has already been stated that the density of the shelter has a 
bearing upon the survival. This is best shown by the following 
records (Table XLVIII) : 

Table XLVIII. — Relation of shelter of boll weevils to their survival. 



Place. 


Date installed. 


Weevils. 


Shelter. 


Survival. 




October 26 

do 


2,436 
2,158 
2,375 
2,850 
2,850 


Average 


Per cent. 
20.00 


Do 


37.76 




October 28 

November 6. . . 
November 10.. 


Average 


5.61 


Do 


23.65 


Do 


Average 


12.70 







RELATION OF CLIMATE TO SURVIVAL. 

Another important consideration in determining the causes for 
high or low survival is the climate. Some of the principal relation- 
ships are brought out in Table XLIX below: 

Table XLIX. — Relation of climate to survival of boll weevils in hibernation. 



Place and year. 



Tallulah, La., 
1910-11. 

Dallas, Tex., 
1907-8. 

Tallulah, La., 
1909-10. 



Descript ion. 



10 cages, variety of 
shelter, installed 
Oct. 15-Dec. 1. 

9 cages, variety of 
shelter, Sept. 21- 
Nov. 18. 

19 cages, great variety 
of shelter, Sept. 16- 
Dec. 14. 



Number 

of 
weevils. 



8,439 
12,087 
21,835 



Per cent 
of sur- 
vival. 



0.5 

.9 

1.4 



Periods of emer- 
gence. 



Feb. 15-June 4 . . 
Feb. 19-June 16 . 
Feb. 15-June 27 . 



Rainfall and tempera- 
ture, Oct. 1-Mar. 15. 



Rain- 
fall. 



Inches. 
8.30 



22.61 
19.34 



Abso- 
lute 
mini- 
mum. 



'F. 

9.5 



15.0 
13.0 



Total 

degrees 

below 

32. 



°F. 
199.5 



233.0 
378.5 



HIBERNATION. 113 

Table XLIX. — Relation of climate to survival of boll weevils in hibernation — €on. 



Place and year. 



Description. 



Number 


Per cent 


of 


of sur- 


weevils. 


vival. 


24,700 


2.1 


22, 179 


4.6 


19,408 


8.9 


30,864 


10.6 


22,463 


12.8 


16,281 


20.0 



Periods of emer- 
gence. 



Rainfall and tempera- 
ture, Oct. 1-Mar. 15. 



Rain- 
fall. 



Abso- 
lute 
mini- 
mum. 



Total 



below 
32. 



Keatchie, La. 
1905-6. 



Mansura, Tex. 
1909-10. 

Calvert, Tex. 
1906-7. 

Dallas, Tex. 

1906-7. 

Victoria, Tex. 
1906-7. 

Mansura, La., 
1908-9. 



18 cages, variety of 
shelter (1 bare), in- 
stalled Nov. 18- 
Dec. 18. 

19 cages, great variety 
of shelter, Sept. 16- 
Dec. 14. 

10 cages, variety of 

shelter, Oct. 1-Dec. 

10. 
10 cages, variety of 

shelter, Oct. 13- 

Dec. 6. 
10 cages, variety of 

shelter, Oct. 25- 

Nov. 29. 
19 cages, great variety 

of shelter, Sept. 28- 

Dec. 21. 



Mar. 22-June 2S . 

Feb. 15-.Iune 15 . 
Mar. 4-July 1 . . . 
Mar. 1-June 19.. 
Feb. ;.'«.-. I une 15. 
Feb. 21-June 29 . 



Inches. 
18.87 



15.37 
11.87 
8.52 
11.25 

10.41 



"F. 
21.0 



19.5 
26.0 
22.0 
27.0 
23.0 



>F. 
91.0 



151.5 
47.0 

145.0 

5.0 

81.0 



One of the most striking features of Table XLIX is the disparity 
between the percentage of survival through the six winters considered. 
A special effort has been made to discover the factors that cause this 
disparity. Among those that have been considered are the absolute 
minimum temperature, the daily accumulated degrees below 32 
during the hibernation season, the number of times a temperature 
below 32° was reached, and the rainfall. Contrary to our expecta- 
tions, it appears that the number of times the temperature descends 
below 32° has no direct effect. However, there seems to be a direct 
relation between the absolute minimum temperature and the rainfall, 
taken together, and the percentage of survival. As the absolute 
minimum ascends and the rainfall decreases the survival seems to 
increase. The greatest survival (Mansura, La., 1908-9) was accom- 

{)anied by the third highest minimum temperature and the third 
owest rainfall during the hibernation season. In the same way the 
next to the highest survival (Victoria, Tex., 1906-7) was accom- 
panied by the highest absolute minimum temperature and the fourth 
lowest rainfall. Conversely, the lowest survival (Tallulah, La., 
1910-11) was accompanied by the lowest absolute minimum tem- 
perature and the lowest rainfall. The next to the lowest survival 
(Dallas, Tex., 1907-8) was accompanied by the third lowest absolute 
minimum temperature and the highest rainfall. It thus appears that 
a moderately cold winter, with temperature frequently near the zone 
of fatal temperatures and excessive precipitation, is very unfavor- 
able for the weevil, but a winter with little precipitation and a tem- 
perature within the zone of fatal temperatures is by far the most 
ratal. Conversely, a winter with temperatures always above 20° and 
moderate precipitation is the most favorable for the weevil. 

28873°— S. Doc. 305, 62-2 8 



114 



THE MEXICAN COTTON-BOLL WEEVIL. 



Certain climatic phenomena are likely to occur which will empha- 
size still more the effects produced by extreme cold and great precipi- 
tation. At Tallulah, La., in 1910-11, the early freeze on October 29 
cut off the food supply and was followed by warm temperatures in 
November which required feeding. The minimum experienced in 
January completed the control and was low enough to counteract the 
small precipitation. 

LONGEVITY OF HIBERNATED WEEVILS. 

From the beginning of the hibernation experiments in 1905 it has 
been the custom to place the emerging weevils in rearing jars or cages 
to determine the average and maximum longevity with and without 
food. The data obtained have a bearing upon the proper time for 
planting and upon other practical points. In these experiments 
9,295 weevils have been used, as shown in Table L. The fed weevils 
were furnished cotton squares as soon as they became available. 
Before that time they were given fresh cotton leaves daily. The 
unfed series was supplied with water only. Both series were placed 
in small cages where general conditions closely approaching those in 
nature were maintained. It should be especially noted that fed 
weevils show over double the longevity of unfed weevils throughout 
the season. 

Table L. — Longevity of hibernated boll weevils after emergence. 





Unfed series. 


Fed series. 


Place. 


Number 

of 
weevils. 


Longevity. 


Number 

of 
weevils. 


Longevity. 




Maximum. 


Average. 


Maximum. 


Average. 


Keatchie, La., 1906 


412 

2,179 

1,079 

1,360 

261 

4 

175 

179 

8 


Days. 
62 
90 
48 
44 
44 
19 
28 
21 
12 


Days. 
17.11 
12.50 
8.07 
8.20 
11.09 
8.75 
8.78 
5.70 
7.25 




Days. 


Days. 


Dallas, Tex., 1907 


901 

715 

1,349 

360 

36 

146 

121 

10 


130 
118 
86 
36 
25 
81 
105 
. 25 


38.20 


Calvert, Tex., 1907 


30.00 


Victoria, Tex., 1907 

Mansura, La., 1909 


14.70 
10.42 


Natchez, Miss., 1909 


12.20 




36.50 


Tallulah , La. , 191 


22.30 


Tallulah, La., 1911 


13.30 






Total 


5,657 






3,638 
















Maximum 




90 


17.11 




130 


38.20 










Weighted average 






10.55 






24.20 















It will be noted that the records of longevity of weevils after 
emergence from hibernation referred to above are based upon speci- 
mens that had passed the winter in artificial hibernation cages. 
However, a number of observations have been made upon the lon- 
gevity of weevils which pass the winter under natural conditions in the 
field. For instance, March 1, 1906, a number of weevils were collected 
from cotton bolls at Brenham, Tex. These were placed in small 
cages and observed daily. The last one died on May 31. Naturally 
the time tliis weevil was deprived of food the preceding fall is not 
known, but it must have been prior to December 1, as the frosts had 



HIBERNATION. 



115 



killed all cotton at Brenham by that date. Assuming that it entered 
hibernation on December 1, it lived six months without food. In 
another case weevils 

40 



collected in the field 
in the spring at Cal- 
vert, Tex. , lived with- 
out food as late as 
June 8. _ This gives 
a duration of life 
without food of six 
months and twelve 
days. Similar ob- 
servations indicate 
clearly that the lon- 
gevity of weevils that 
pass the winter in 
artificial cages is a 

{>roper index to the 
ongevity of those 
which pass the win- 
ter in the field. 

It has become 
quite apparent from 
a study of the records 
that the longevity of 
weevils provided with food is considerably greater with weevils emer- 
ging in June than with those emerging in March, while, on the con- 
trary, with unfed weevils the longevity decreases with the lateness of 
emergence. (Table LI.) 

The diagram (fig. 25) illustrates the above statement graphically. 

















./ 




<W&MseLO. 


^mrorreofl 




















A vj°>0^ 










^^><£ 













35 



30 



\20 

Q 

/5 



/O 



Fig. 25.— Diagram illustrating average longevity of boll weevils after 
emerging on a given date. ( Original. ) 



Table LI. — Latest dates of death of hibernated boll weevils. 



Time of emergence. 



Feb. 15-28. 
Mar. 1-15.. 
Mar. 16-31 . 
Apr. 1-15.. 
Apr. 16-30. 
May 1-15. . 
May 16-30. 
June 1-15. . 
June 15-30. 



Entire season. 



Unfed weevils. 



Mansura, 
La., 1910. 



Mar. 18 
Apr. 13 
Apr. 20 
Apr. 28 
May 13 
May 29 
June 12 



June 12 



Weevils fed foliage. 



Tallulah, Mansura, 
La., 1910. | La., 1910. 



Apr. 1 
Apr. 12 
Apr. 28 
May 21 
June 1 
June 15 
June 27 



June 20 

July 5 

June 28 

Julv 15 

Julv 12 

July 29 



Tallulah, 

La., 1910. 



June 21 
June 18 
Julv 15 
Julv 26 

July 7 



June 27 July 29 | July 26 



Weevils fed squares. 



Mansura, 
La., 1910. 



July 19 



July 19 



Tallulah, 
La., 1910. 



Sept. 13 
July 1 
Aug. 31 



Sept. 13 



MAXIMUM LENGTH OF LIFE. 



In connection with Table LI it will be noticed that the latest known 
recorded death of a hibernated weevil is September 13. This fact, 
taken in conjunction with Table LII, showing the maximum longevity 



116 



THE MEXICAN COTTON-BOLL WEEVIL. 



of weevils from the time of entering hibernation to death, is of great 
interest. The maximum Longevity of 335 days, or 11 months, gives 
proof of the wonderful vitality of the boll weevil. 

Table LII. — Longevity of hibernated boll weevils from installation to death. 



Place. 



Mansura, La., 1910 

Tallulah, La., 1910.... 

Mansura, La., 1910 

Tallulah, La., 1910 

Mansura, La., 1910 

Tallulah. La., 1910.... 



Condition. 



Unfed 

....do 

Fed foliage.. 

....do 

Fed squares. 
....do 



Longevity. 



Average. 


Maximum. 


Days. 


Days. 


158 


an 


ItiO 


243 


206 


256 


221 


37a 


257 


367 


262 


335 



RELATION OF EMERGENCE AND LONGEVITY TO TIME OF 

PLANTING. 

The data that have been presented show the extreme importance 
of early planting as a means of averting damage by the boll weevil. 
Early planting takes advantage of the portion of the season when the 
weevils are present in the fields in smallest numbers. The longer 
planting is deferred the greater the number of weevils which will 
nave emerged. The advantage of an early crop has been shown in 
many experiments by the Bureau of Entomology and by practical 
cotton planters. On the other hand, the experience in late plantings 
has been disastrous. The obvious explanation is in the prolonged 
period of emergence and the remarkable ability of the weevils to live 
without food after emergence. This topic will receive additional 
treatment under the heading of "Repression." 



NATURE OF WEEVIL ACTIVITY FOLLOWING EMERGENCE FROM 

HIBERNATION. 

In the section dealing with the spring movement we have discussed 
the early search of the weevils for food. There are certain points 
connected with the spring movements, however, which are intimately 
related to hibernation, and these will be dealt with here. 

1 Tn following the activity of emerged weevils at Dallas, Tex., 
certain specimens were marked in such a way as to make it possible to 
recognize them individually, and the weevils were allowed to remain 
practically undisturbed in the section where they had spent the 
winter. In making the daily examinations record was kept of the 
appearance or disappearance of each individual weevil. No food was 
supplied in any of the sections until toward the close of the experi- 
ments in May, when seed was planted and cotton began growing 
before the last weevils emerged. A majority of the weevils were 
seen a second time, ami some disappeared and reappeared as many 
as eight times. The longest period between the first and second 
appearance of any individual was 43 days. 

1 From Bull. 77, Bureau of Entomology, pp. 50, 51. 



HIBERNATION. 



117 



Table LIII. — Intermittent activity oj unfed boll weei Us after emergence, at Dallas, Tex., 



1906. 







Number of R 1 






i mated"— 


i 

3 

c 






























'J' H 


'J bra 


— •/, 


















■e-c 

k. — 






























i 

'- 


f- 


S3 
1 


g 

e 


5 

s 


I 

/- 


| 

e 
; 
-- 
■i. 


I 

3 


?■ 


£ 


2 
?■ 


•/'. 

t 


3 


* 

- 


= 
/ - 

f 

< 


46 


2i 


IS 


11 


6 


2 


2 


I 


17 


• : 


6 


1 2 


•I 




6.8 



The observations recorded in Table LIII Bhow conclusively that wee- 
vils may leave their winter quarters during warm days and, failing to 
find food, they may again become quiet and emerge again after a con- 
siderable interval. This fact has an important bearing upon the 
proposition which is frequently advanced by planters of starving the 
weevils in the spring by deferring the time of planting. While many 
weevils might perish in this way, it is certain that many more would be 
able to survive and reappear at intervals, so that there would be plenty 
of weevils to infest the crop, even though this might be planted as 
late as is possible to secure any yield. 

Other observations were made upon the intermittent activity of 
unfed weevils during the spring of 1906. Weevils from Calvert, Vic- 
toria, and Brenham, Tex., were tested. The weevils from Calvert 
and Victoria had been confined in hibernation cages throughout the 
winter. Those from Brenham were collected in the field! early in 
March. None of these weevils had tasted food after emergence. 
The results are shown in Table LIY. In this table the date of death, 
unless otherwise indicated, is considered as having been the middle 
date between the last examination at which a weevil was found alive 
and that at which it was found dead. 

Table LIV. — Intermittent activity of unfed emerged boll weevils, 1906.* 



Locality. 



Brenham, Tex . 



When 
collected. 



1905 



Calvert, Tex Nov. 25 

Victoria,Tex g£ 7 .g 



1906 

Nov. 



When 

put in hi- 
bernation. 



1906 

Nov. 27 
Nov. 7, 13 
Dec. 11 



When 
removed 

from hi- 
bernation. 



1906 
Apr. 19 

Apr. 6 
Mar. 1 



Whin 
rehiber- 



1906 
Apr. 23 

Apr. 16 
Mar. 7 



Weevils 
put in rehi- 
b*-rnation. 



Date of 
first ex- 
amina- 
tion. 



May 10 
Apr. 24 

May 11 



Locality. 



Weevils 

surviv- 
ing. 



second 

exami- 
nation. 



Weevils 

surviv- 
ing. 



Date of 

third 
exami- 
nation. 



surviv- 
ing. 



Date of 
death of 
longe l 

survival. 



A verage 
length of 

life in 
rehi tar- 
nation. 



Calvert, Tex.. 
Victoria, Tex. 

Brenham, Tex 



May 22 

May 10 

May 23 



June 8 



May 31 



June 8 
Mav 10 
Mav 31 



Days. 
30.4 
19.1 
67.4 



From Bulletin 77, Bureau of Entomology, p. 52. 



118 



THE MEXICAN COTTON-BOLL WEEVIL. 



The records for Calvert and Brenham show a very remarkable 

f)ower of endurance in some weevils, the average survival for the two 
ots of 20 and 8 weevils being over 30 and 60 days, respectively. 

NATURAL CONTROL. 

Considerable attention has been given to the study of the natural 
forces which control the boll weevil. These studies have revealed a 
large amount of important data, some of which have been used in 
several bulletins. In the present publication it is possible to give 
only a summary of the most important results. 

In general, the natural agencies which control the boll weevil may 
be classified as climatic (consisting principally of heat which kills 
directly and also indirectly by rendering the food supply unsuitable, 
and dryness, the effects of which are intermingled with those of heat), 
plant resistance, parasites and other insect enemies, diseases, and 
birds. Each of these agencies will be discussed separately, but a 
general summarization may be of value. Table LV is a summary of 
the observations made in the years 1906 to 1909 on weevil stages from 
many localities. It deals with the mortality of immature stages from 
all causes exclusive of plant proliferation. 



Table LV. 



-Annual mortality of immature boll weevils in all classes of cotton forms. 
1 906-1 909. 



Year. 


Total 
forms 
ex- 
amined. 


Total 
stages 
found. 


Total 
stages 
dead. 


Number stages killed 
. by- 


Percentages of mortality 
due to — 


Clim- 
ate. 


Preda- 
tors. 


Para- 
sites. 


All 
causes. 


Clim- 
ate. 


Preda- 
tors. 


Para- 
sites. 


1906 


100,644 
21, 980 
72,234 
27, 857 


40,073 
13,405 
29, 546 
11, 653 


22, 353 
7,275 

13, 103 
4,863 


10, 078 
3,896 
6,268 
3,012 


10, 547 
2, 263 
3,878 
1,231 


1,728 

1,116 

2,957 

620 


55.81 
54.27 
44.34 
41.73 


25.15 

29.06 
21.21 

25.84 


26.31 
16.88 
13.12 
10.56 


4.31 


1907. 


8.32 


1908 


10.00 


1909 


5.32 






1906-1909. . . . 


222, 715 


94, 677 


47, 594 


23, 254 


17,919 


6,421 


50.26 


24. 56 


IS. 92 


6.78 



Inasmuch as the material used in making the examinations was 
derived from many sources and in different proportions each year, a 
system of weighting the different kinds of material was devised. 
Table LVI presents a summarization of this weighting in terms of 
percentages of mortality: 



Table LVI. 



•Weighted average mortality of the boll weevil, 1906-1909, due to various 
causes. 



Year. 


Prolifera- 
tion.' 


Climate. 


Preda- 
tion. 


Parasit- 
ism. 


Total. 


1906 ■ 


Per cent. 
12.42 
12.42 
12.42 
12.42 


Per cent. 
24.39 
28.16 
17.83 
23.01 


Per cent. 
24.85 
16. IS 
11.77 
10.92 


Per cent. 
2.94 
3.83 
6.34 
2.63 


Per cent. 
64.61 


1907 


60.61 


1908 


48.37 


1909 


48.99 






1906-1909 


12.42 


24.45 


15.93 


3.93 


56.73 







1 The average determined in 1906 (see Bull. 59, Bureau of Entomology) is used to apply to other years. 



NATURAL CONTROL. 



119 



The extensive series of examinations tabulated above (Table LVI) 
were made upon immature weevils in all conditions of squares and 
bolls, the principal of which are known as hanging dry squares, 
fallen squares, hanging dry bolls, and fallen bolls. The conditions 
in these four classes of material vary greatly as does the mortality, 
as is shown in Table LVII. The apparent discrepancy between the 
totals in Table LVII and in Table LVI is due to the admission of 
other minor classes of material in the first table. This table (LVII) 
also excludes mortality from plant proliferation. 



Table LVII. 



Mortality of immature boll weevils in various classes of cotton forms, 
1906-1909. 



Class of infested 


Total 

forms 

exam- 
ined. 


Total 
stages 
found. 


Total 
stages 
dead. 


Number stages killed 
by- 


Percentages of mortality due to- 


forms. 


Cli- 
mate. 


Preda- 
tors. 


Para- 
sites. 


All 

causes. 


Cli- 
mate. 


Preda- 
tors. 


Para- 
sites. 


Fallen squares 

Hanging squares. . 
Hanging bolls , , . 
Fallen bolls 


107, 293 
24,683 
41,738 
46,200 


63,985 
14, 390 
8,737 
6,825 


34, 403 
7,084 
3,328 
2,375 


17,596 
2,543 
1,709 
1,128 


13,958 
1,745 
1,054 
1.148 


2,849 

2,796 

565 

99 


53.76 
49.22 
38.09 

34. 79 


27.50 
17.67 
19.56 
16.52 


21.81 
12.19 
12.06 
16.80 


4.45 

19.43 

6. 47 

1.45 


All classes... 


219,914 


93,937 


47, 190 


22, 976 


17,905 


6,309 I 50.23 


24.45 


19. 00 


6.71 



Still another extremely important aspect of this large series needs 
to be shown. This is the geographical differences in the control by 
climate, predators, and parasites. 

Table LVIII. — Average mortality of immature boll weevils in various classes of cotton 
forms by States, 1906-1909. 



Class of forms and State. 



Fallen squares. 

Arkansas 

Louisiana 

Mississippi 

Oklahoma 

Southwest Texas 

Southern Texas 

Fast Texas 

Central Texas 

Northeast Texas 

North-Central Texas 

Hanging squares. 

Arkansas 

Louisiana 

Mississippi 

Oklahoma 

Southwest Texas 

Southern Texas 

Fast Texas 

Central Texas 

Northeast Texas 

North-Central Texas 



Total 
forms 
exam- 
ined. 



374 

28,204 

4,216 

667 

2, 757 

38, 007 

825 

14,879 

10,318 

7,066 



1,612 

8,601 

784 

100 

89 

5.740 

192 

2,094 

4.044 

1.992 



Total 
stages 
found. 



162 
15,177 
2,661 

442 

1,390 

25,063 

464 
7,028 
6, 197 
4,501 



1.144 

5,184 

499 

63 

46 

3,626 

L35 

1,052 

1,007 

1,141 



Total 
stages 
dead. 



02 

4,895 

1,070 

238 

390 

16, 965 

248 

4,233 

3.439 

2,863 



494 

2,182 

182 

26 

24 

1,937 

10 

703 

887 

766 



Stages killed by- 



Cli- Preda- 
mate. tors. 



43 

1,990 

410 

100 

186 

8,547 

136 

2,386 

1,812 

1,980 



188 

881 

41 

6 

6 

727 

5 

253 

290 

190 



17 

2,243 

263 

117 

152 

7,377 

107 

1,602 

1,347 

633 



60 
651 
34 



2 

496 

1 

208 

211 



Para- 
sites. 



2 

562 

391 

21 

52 

1,041 

5 

245 

280 

2,50 



246 

650 

107 

20 

16 

714 

4 

242 

386 

492 



Mortality due to- 



All 
causes. 



P.ct. 
38.27 
32.25 
40.21 
53.84 
28.06 
67.68 
53.44 
55.49 
52. 93 
63.60 



43.18 
42.09 
36.47 
41.27 
52. 10 
53. 41 
7.40 

60.82 
53.80 
67.13 



Cli- 
mate. 



P.ct. 
20.54 
13. 11 
15.63 
22.62 
13. 38 
34.10 
29.31 
31.28 
27.89 
43.99 



16.43 

16.99 

8.21 

9.53 

13.00 

20.04 

3.70 

24.04 

17.39 

17. 17 



Preda- 
tors. 



p. a. 

10.49 
14.77 
9. SS 
20. 47 
10. 93 
29.43 
23.00 
21.00 
20. 73 
14.00 



5.24 
12.55 
6.81 
0.00 
4.30 
13.67 
0.74 
19.75 
12.66 
7.71 



Para- 
sites. 



P.ct. 
1.23 
3.70 
L4.69 

4.75 
3.74 
4.15 
1.07 
3.21 
4.30 
5.55 



21.50 
12.53 
21.44 
31.74 
34.70 
19. 69 
2.96 
22. 98 
23.15 
43. 12 



120 THE MEXICAN COTTON-BOLL WEEVIL. 

Although the grand total of the examinations shows a higher mor- 
tality due to fallen squares than to hanging squares, it is noticeable 
that the mortality in hanging squares is greater in Arkansas, Louisi- 
ana, southwestern, central, northeastern, and north-central Texas, 
and less in Mississippi, Oklahoma, and southern and eastern Texas. 

As shown in Table LVIII, the highest mortality in fallen squares is 
67.68 per cent in southern Texas and the lowest 28.06 per cent in 
southwestern Texas. In hanging squares the highest mortality is 
67.13 per cent in north-central Texas and the lowest, 7.40 per cent, in 
eastern Texas. 

Climatic control is highest in fallen squares in north-central Texas, 
at 43.99 per cent, and lowest in Louisiana, at 13.11 per cent, while 
in hanging squares it reaches 24.04 per cent only in central Texas and 
is as low as 3.70 per cent in eastern Texas. 

Predatory control in fallen squares is highest in southern Texas, 
at 27.43 per cent, and lowest in Mississippi, at 9.88 per cent, while in 
hanging squares its highest average is 19.75 per cent in central Texas 
and its lowest no per cent in Oklahoma. 

Parasitic control in fallen squares is highest in Mississippi, at 14.69 

Eer cent, and lowest in eastern Texas, at 1.07 per cent. On the other 
and, in hanging squares it is highest in north-central Texas, with 
43.12 per cent, and lowest in eastern Texas, with 2.96 per cent. 

In fallen squares it is generally the case that over half of the mor- 
tality is due to climate, but in Louisiana, Mississippi, Oklahoma, and 
southwestern Texas insect control is greater than climatic. In 
hanging squares the insect control is invariably greater than climatic 
control, and in Mississippi, Oklahoma, and southwestern and north- 
central Texas parasitic control alone is greater than the climatic plus 
the predatory control. It was shown in the table comparing the total 
mortality in all classes of forms (Table LVII) that the weighted 
average mortality due to insects was 25.77 per cent, as against 24.45 
per cent due to climate. All of this evidence is cited to show that in 
reality the insect enemies produce a very large proportion of the mor- 
tality of the boll weevil and should therefore be encouraged in every 
way possible. Of course, it is evident that climatic control is even 
superior, because of the influences it brings to bear upon every phase 
of the weevil's existence. 

Regional comparisons such as have been made above are of the 
greatest importance in determining what factors in natural control 
need to be given the greatest encouragement by cultural expedients 
or otherwise. 

CLIMATIC CONTROL. 

From almost every viewpoint the climatic control of the boll weevil 
is the most important which this insect experiences. The weevil 
reacts to a multitude of conditions of temperature and humidity. 
The time of entrance into hibernation, the length of the hibernation 
period, the time of emergence from hibernation, the length of the 
various immature stages, the rate of oviposition, and even the pro- 
portion of sexes are profoundly affected by these agencies. In many 
cases their effects are not direct. They may affect the weevil indi- 
rectly through the cotton plant. For example, drought may interfere 
with the fruiting of the cotton plant and thus deprive the weevils of 
food. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XIV. 




Natural Control of the Boll Weevil. 

o, Pilose and nonpilose steins of cotton; b, larva of boll weevil crushed by proliferation; c , pupa 
of Catolaccus inccrtus on pupa of cotton boll weevil; d, larva of MicTobracon mellitor attacking 
boll-weevil larva; r.f, holes gnawed by Solenopsis gcminala in effecting entrance into infested 
squares. (Original.) 



NATURAL CONTROL. 121 

The most conspicuous illustration of the climatic control of the 
weevil lies in the failure of the pest to establish itself in the drier 
portions of Texas. For several years multitudes of weevils have 
flown from the more humid portions of Texas to the west, where the 
climate is drier. In fact, every year there has been a large inflow of 
weevils into this region. Every season, however, the conditions have 
practically immediately prevented the establishment of the weevil. 
The most important factor has been dryness, but there are others that 
must be considered. Among them is the fact that there is com- 
paratively little winter protection for the insect. In addition, an 
indirect result of small precipitations is the growth of cotton plants of 
only small size. This results in a small amount of shade and thus 
augments the direct effect of heat and dryness upon the infested 
squares which fall to the ground. 

Frequently the effects of climate act upon the enemies of the boll 
weevil. This is the case where heat destroys the weevils and their 
parasites in squares that fall to the ground. In several cases, how- 
ever, heat increases the effectiveness of the enemies of the weevil. 
A striking example of this was observed on September 2, 1911, by 
Mr. J. D. Mitchell, of the Bureau of Entomology. A succession of 
da3 r s in which the temperature was very high and the air exceedingly 
dry caused the premature opening of many cotton bolls in the vicinity 
of Victoria, Tex. Prior to this time the weevils had destroyed prac- 
tically all of the squares, and many immature stages were to be found 
in the bolls thus forced open. In such instances the exposed imma- 
ture stages of the weevil were subjected to two important destructive 
agencies. Heat killed many that became exposed to the air, and the 
ants were able to reach not only those that were exposed, but others 
inside of the partially opened bolls. If the bolls had not opened, 
such weevils would have been beyond the reach of the ants. As it 
was, the climatic conditions not only directly destroyed large num- 
bers of weevils in a situation where climatic factors rarely affect them, 
but also greatly increased the effectiveness of another unrelated factor 
of control. 

CLIMATIC INFLUENCES ON VITALITY AND ACTIVITIES. 

In the preceding pages numerous effects of climate upon the devel- 
opment and activities of the boll weevil have been pointed out, but 
these must be summarized in order to show how intimately connected 
the climate is with every phase of the weevil's life. It appears that 
the movements of the weevil are sluggish or active in accordance with 
the nature of the day, cloudy days or low temperatures always causing 
them to be more sluggish. The number of feeding punctures per 
square decreases with increases in temperature, and the time before 
falling of a punctured square also decreases with higher temperatures. 
In like manner the length of life of the weevil decreases. The age of 
beginning copulation and the age of beginning oviposition are both 
increased by decreases in temperature. The activity in oviposition, 
which is found to begin at 75° F., is greatest in the hottest time of the 
day, cloudy days causing the oviposition to be less active. The num- 
ber of eggs per day increases with the temperature and varies for any 
given temperature with the humidity. The entire period of develop- 
ment increases as the temperature and atmospheric humidity decrease. 



122 THE MEXICAN COTTON-BOLL WEEVIL. 

The number of generations decreases with the mean temperature and 
mean humidity. 

Hibernation seems to begin at mean temperatures between 56° F. 
and 60° F., but is hastened by high humidity. Cold nights followed 
by warm, still days seem to stimulate the weevils to considerable 
activity in the fall, evidently warning them to seek hibernation quar- 
ters. The period of entrance into hibernation is much more rapid as 
the mean humidity and mean temperature become lower. The 
emergence of the weevil is in like manner influenced by the tempera- 
ture, but it must be considered that the actual temperature experi- 
enced by the weevil is that which affects the emergence. The time of 
emergence apparently depends upon an accumulation of a certain 
amount of effective temperature and a certain amount of rainfall, but 
if more than the necessary temperature accumulates less rainfall will 
be needed, and vice versa. The majority of weevils emerge at mean 
temperatures between 64° F. and 78° F. The percentage of survival 
seems to decrease as the absolute minimum temperature decreases 
and the rainfall increases. 

The foregoing statements are conclusions based in some cases upon 
more or less fragmentary information, but in other cases they may 
almost be considered as laws of climatic control. 

FIELD OBSERVATIONS ON MORTALITY DUE TO HEAT AND DRYNESS. 

Heat and dryness affect the weevil in a very simple manner. Un- 
less the square remains moist the food supply becomes unsuitable. 
In other cases the heat itself causes death directly. Therefore, the 
hotter and drier the ground upon which the infested square falls, the 
more certain is the death of the weevil. 

In the years 1906 to 1909 an exhaustive study was made of the 
effects of various climatic and other agencies which control the boll 
weevil. In this work 222,715 cotton forms (including bolls and 
squares) were collected by agents of the Bureau of Entomology at 65 
localities in Texas, 26 in Louisiana, 7 in Oklahoma, 6 in Arkansas, and 
6 in Mississippi. Careful laboratory observations were made to deter- 
mine the mortality due to heat or dryness and to other factors. 

By reference to the series of general tables (LV-LVIII) at the 
beginning of the discussion of natural control it will be noticed that 
climatic control kills practically one-fourth of the developing stages, 
the average for the four years in which records were made being 24.56 
per cent, which was slightly surpassed by the total insect control. 
The highest average climatic control was obtained hi 1907, being 29.06 
per cent, while in 1908 it averaged only 21.21 per cent. 

In rearranging the data to ascertain the condition in which the 
control was greatest we find the following results: Fallen squares, 
27.50 per cent; hanging dry bolls, 19.56 per cent; hanging dry squares, 
17.67 per cent; and fallen bolls, 16.52 per cent. 

The geographical distribution of climatic control is very interesting. 
In fallen squares the various sections ranked as follows: North-central 
Texas, 43.99 per cent; southern Texas, 34.10 per cent; central Texas, 
31.28 per cent; eastern Texas, 29.31 per cent; northeastern Texas, 
27.89 per cent; Arkansas, 26.54 per cent; Oklahoma, 22.62 per cent; 
Mississippi, 15.63 per cent; southwestern Texas, 13.38 per cent; 
Louisiana, 13.11 per cent. 



NATURAL CONTROL. 



123 



In hanging squares we find a somewhat different arrangement of 
the sections: Central Texas, 24.04 per cent; southern Texas, 20.04 
per cent; northeastern Texas, 17.39 per cent; north-central Texas, 
17.17 per cent; Louisiana, 16.99 per cent; Arkansas, 16.43 per cent; 
southwestern Texas, 13 per cent; Oklahoma, 9.53 per cent; Mississippi, 
8.21 per cent; and eastern Texas, 3.70 per cent. 

In many of the records made during 1906 it became evident that 
certain cultural practices greatly favored the amount of control by 
heat and dryness. The wider the rows, the greater the amount of 
sunlight which strikes the ground. Consequently the fields with wide 
rows or in which the stand was imperfect showed the greatest mor- 
tality. In a similar way, fields in which were varieties with compara- 
tively small amounts of leafage showed greater mortality due to heat 
and dryness. It did not become apparent, however, from the obser- 
vations made, that the direction m which the rows ran made any 
material difference in the mortality. 

The difference between the various sections in the mortality in 
fallen squares is especially conspicuous. This is due undoubtedly 
primarily to the greater precipitation in the sections with low mor- 
tality, which, by keeping the ground more or less moist, prevents 
such temperatures at the surface as are frequently reached in Texas. 
The greater rainfall in Louisiana also undoubtedly has an indirect 
effect. In that State the additional rainfall causes the cotton plants 
to grow to a large size and to shade the ground more than is the case 
in Texas, thus preventing the sun from reaching the squares on the 
ground. The differences in hanging squares are not quite so con- 
spicuous, but are probably due to some extent to atmospheric humid- 
ity, density of foliage, and other similar factors. 

Equally interesting results were obtained in 1906 with reference to 
the effect of heat and dryness upon the different stages of the boll 
weevil. It was found that the mortality in the larval stage amounted 
to 52 per cent, in the pupal stage to 18 per cent, and in the adult stage 
to 6 per cent. Nearly 70 per cent of all the mortality caused by heat 
and dryness occurs, therefore, during the larval stage. 

Table LIX illustrates the percentage of stages killed during the 
warm months of the year by high temperatures and is based upon all 
of the examinations made during the years 1906 to 1909, inclusive. 

Table LIX. — Weighted average heat control of immature stages of the boll weevil, by 
months, Texas, Louisiana, Oklahoma, Arkansas, and Mississippi. 



Month. 



Forms 

exam- 
ined. 



Stages 
found. 



Per cent 
killed by 
heat ami 
drying. 



May 

June 

July 

August 

September. 
October. .. 

Total 



100 
16,930 
43,050 

80,923 
.37,378 
17,344 



56 
10,708 
21,758 
33,170 
17,107 
8,283 



195,734 



91,082 



7.20 
28.33 
25.61 
24.62 
22.87 
16.59 



23. 80 



Many illustrations are available to show the powerful effect of heat 
and dryness in the reduction in the numbers or boll weevils in cotton 
fields. The action of this agency is so powerful that it may check the 



124 



THE MEXICAN COTTON-BOLL WEEVIL. 



weevils in a single season so that a crop may be obtained. This was 
shown in a field which was under observation in Victoria County, 
Tex., in 1906. It was found in April that a very large number of 
hibernated weevils appeared in the field. This month was reasonably 
moist, so that the cotton germinated promptly and made a quick 
growth. The month of May, however, showed a decided deficiency 
in precipitation, being more than 3 inches below the normal for the 
month. This checked the weevil at the time the first infested squares 
began to drop. The control continued during the month of June, 
which also showed 3 inches less than the normal rainfall. These 
conditions resulted in such a checking of the weevils by June that the 
cotton plants were able to put on a large number of squares. The 
month of July showed a precipitation above the normal, which caused 
the plants to grow rapidly. The setback experienced by the weevils, 
however, during the preceding dry period was so great that they 
were unable to overtake the production of fruit, so that a yield of about 
one-fourth of a bale per acre was obtained. 

Examples of such complete control within a single season are not 
common. It frequently happens that a drought continues so long 
that the plants are seriously affected. In general, however, the 
plants can recover more rapidly from a drought than the weevil. 
This results in an advantage to the crop from even a short drought. 
Of course the advantage becomes greater as the drought is prolonged, 
provided it is not prolonged to a point where it seriously affects the 
growth of the plants. Examples of the control of the weevil in one 
season from heat and dryness of the preceding season are common. 
Table LX shows a striking instance of this kind. It will be seen that 
the effects of the drought of 1902 extended into the following season 
and brought about a marked increase in production. By the follow- 
ing year (1904) the recovery of the weevils from the drought of 1902 
was indicated by a decreased production of cotton. 

Table LX. — General illustration of drought control of the boll weevil, Nueces County 

Tex., 1901-1904. 







Rainfall. 






Temperature. 


Cotton 
produc- 




















Annual. 


Mar. l-Aug.31. 


Annual. 


Mar. l-Aug.31. 


tion, 
Nueces 


















County, 
equiva- 
lent in 
500- 


Year. 


Mean 


Depar- 
ture 


Mean 


Depar- 
ture 


Mean 


Depar- 
ture 


Mean 


Depar- 
ture 




aver- 


from 


aver- 


from 


aver- 


from 


aver- 


from 


pound 




age. 


nor- 
mal. 


age. 


nor- 
mal. 


age. 


nor- 
mal. 


age. 


nor- 
mal. 


bales. 




Inches. 


Inches. 


Inches. 


Inches. 


"F. 


°F. 


"F. 


"F. 




1901 


17.49 
22.22 
36.92 
28.54 


-11.90 

- 7.98 
+ 6.72 

- 1.66 


6.74 

5.57 

25.97 

13.56 


- 7.42 

- 7.39 
+11.38 
+ .83 


70.7 
71.5 
69.1 
70.5 


0.0 
+1.4 
— .9 
+ .4 


76.2 
77.3 
74.5 
76.0 


+0.83 
+1.85 
- .9 
+ .5 


601 


1902 


480 


1903. . 


4,099 


1904. . 


1,556 







NATURAL CONTROL. 125 

GENERAL DISCUSSION OF THE RELATIONS OF TEMPERATURE TO THE 

BOLL WEEVIL. 

Our studies of the boll weevil lead us to the conclusion that there 
is a certain degree of temperature above which, under any condition 
of humidity, no individuals can exist even for a limited time. This 
point is known as the maximum fatal temperature. Below this there 
is a zone of varying width of temperatures which may be fatal in 
cases of long exposure or under certain conditions of humidity or 
insect vitality. This may be known as the upper zone of fatal tem- 
peratures. Below the zone of fatal temperatures is a zone of tem- 
peratures which, when continuing for any length of time, force the 
insects to shelter. This zone may therefore be fitly called the zone 
of sestivation, and it must be understood that the relative humidity 
will have a strong influence in moving this zone upward or downward, 
according to regional conditions. This zone is limited by the point 
at which effective temperature ceases. Below this point is the zone 
of activity. In this zone will be found the degree of effective tem- 
perature, a long continuance of which is necessary to draw the insects 
out of hibernation. This is not an absolutely fixed point, for it 
varies with humidity. 1 Possibly the relation could be stated in a 
definite formula if a sufficient amount of data was available. 

The temperature which causes activity is usually known as the 
zero of effective temperature. It is assumed that active metabolism 
begins at this point and that a certain amount of effective tempera- 
tures accumulated in daily units is necessary to bring about a given 
transformation or function. This sum is known as the total effective 
temperature for any given function. It will vary in accordance with 
the humidity. Below the zero of effective temperature there will 
be no necessity of feeding, and locomotion rapidly becomes impossi- 
ble. On the approach of the zero of effective temperature the 
insects will display considerable activity in finding winter quarters. 
We therefore designate the zone below this zero as the zone of hiber- 
nation. The lower limit of this zone is the highest temperature 
which may be fatal under certain conditions of humidity or rapid 
alternation of temperatures. Below this point occurs a more or less 
restricted lower zone of fatal temperatures. The lowest point at which 
life can exist is known as the minimum fatal temperature. 

1 Of course the manifestation of the absolute temperature which draws the weevils out of hibernation is 
dependent upon the density of shelter. Certain forms of shelter prevent the weevils from being affected 
until long after the outside air has been sulliciently warm to cause activity. 



126 



THE MEXICAN COTTON-BOLL WEEVIL. 



These zones are illustrated in the accompanying diagram (fig. 26). 

UPPER ZONE OF FATAL TEMPERATURE. 

Numerous experiments have been conducted in dropping adult 
boll weevils upon the soil at different temperatures to determine the 

effects upon the insect. 



/40 



/jo 



/20 



//o 



/oo 



90 

|. 

So 



40 



fs30 



20 



to 



-4-M/IX/MOM £Z7XL r£AfP£PHTl//?£ 



>UPP£PZOA/£OF/%7XL T£MP£&rri//?£S 



\ZOM£OF/l£Sr/Mr/OA/ 



In this work 119 tests 
were made at soil tem- 
peratures varying from 
110° to 140° F. Below 
122° F. none of the wee- 
vils were killed, but from 
122° F. upward death re- 
sulted in times varying 
from 1 second to 900 
seconds. In a general 
way the exposure neces- 
sary to cause death de- 
creased as the tempera- 
tures became higher. 
From these experiments 
we conclude that the 
upper zone of fatal tem- 
perature for the adult 
boll weevil may be con- 
sidered as from 122° to 
140° F. 

In the series of exper- 
iments to which refer- 
ence has been made a 
number of observations 
were made upon humid- 
ity. The atmospheric 
humidity during the time 
the experiments were 
under way, however, was 
rather constant, ranging 
from 37 per cent to 40 
per cent. Within this 
narrow range it was not 
determined that humid- 
ity either decreased or 
increased the length of 
time necessary to cause 
the death at any fixed 
temperature. 

It is interesting to 
note that the zone of 
fatal temperature for 
adult weevils which fall 
to the ground will be 
reached under general conditions when the temperature recorded 
at the usual distance above ground at which thermometers are placed 
reaches 95° F. 



\ zo#£0£*CT/vyrv 



]<r-FOM>/SP£0(//P££> s40OlS£ rWSPO/ATT 

}-Z£POOP£PP£C77^£ 7EWP£/W7V/?£ 
ZONEO£H/B£PM/)r/OM/ r 0PMA1'ArVP£S7HG£S 
-FJZ4L. T£fifP£/?/17VP£ POP £66S *M0 yvt/W UPM4£ 
)zOME OF ff/B£PA//mOW PUP MOULTS 



)LOiV£PZO/V£OF&i7XL 7£MP£ft/ITVP£S 



'■4r-MM/WAt PHT/U. 7£M0£&I7VP£ 



Fig. 26.— Diagram to illustrate the zones of temperature in their 
relations to the activities of the boll weevil. (Original. 1 



NATURAL CONTROL. 127 



ZONE OF ESTIVATION. 



During 1906 and 1907, in southern Texas, Mr. J. D. Mitchell ob- 
served that many adult weevils were on the ground near the cotton 
stalks under clods of earth and dead leaves, seeking protection from 
the intense heat. This indicates a distinct zone of aestivation, 
although such temperatures may exist only for a few hours at a 
time. The exact limitations of this zone are undeterminable. 
/Estivation is a very common habit among weevils. As throwing 
some light on the probable action of the boll weevil under high tem- 
peratures, it is of interest to state that Prof. C. H. T. Townsend, of 
Piura, Peru, finds that the Peruvian cotton square borer, Antho- 
nomus vestitus Boheman, activates during the not months in the 
fallen squares both as pupa and adult, but remains practically 
inactive. 

ZONE OF ACTIVITY. 

The temperatures at which most of the functions of the boll weevil 
are exercised lie between the means of 91° F. and 56° F. It is prob- 
able, however, that this zone approaches very close to the zone of fatal 
temperatures. In the spring effective temperature ' begins to accu- 
mulate at approximately 56 degrees, but the total necessary to bring 
the weevils out of hibernation may be low if the rainfall and humidity 
for the same period are high, and it must be correspondingly high if the 
humidity is low. 2 When the two factors have accumulated enough 
between them they bring about emergence. It is roughly calculated 
that 172° of effective temperature and 5.1 inches of rain are necessary. 
A deficiency of effective temperature must be balanced by additional 
rainfall; a deficiency of rainfall must be balanced by additional effec- 
tive temperature. For a fuller discussion of this subject see the 
section on emergence from hibernation (p. 107). 

When the weevils have emerged and found food they require a cer- 
tain number of days of feeding before oviposition can take place. 
This preoviposition period for hibernating weevils and for the succeed- 
ing generations is determined largely by temperature and humidity. 

As these two factors decrease the period increases. In like manner 
we have shown on preceding pages how the egg and larval and pupal 
stages are governed by the same laws. We have also shown that even 
the daily rate of oviposition is accelerated by increases in temperature 
and probably also of humidity. 

The common impression that "rain brings the weevils" has its basis 
in the natural increase in the numbers of weevils shortly after a rainy 
period, due somewhat to the fact that increased humidity reduces the 
developmental period. A more important factor, however, is that 
humidity reduces the effects of sunshine in killing the weevil stages. 

ZONE OF HIBERNATION. 

The behavior of the weevils in hibernation is fully discussed else- 
where. In ice-box experiments at 45° F. it was found that the weevils 
would not emerge, but Dr. W. E. Hinds found that 10 weevils which 
had emerged from hibernation and which were confined 303 weevil 

1 That is, the temperature at which activity begins . 

' In a former publication (Bull. No. 51) we adopted the assumption made by other writers that 43° F. 
is the general zero of effective temperature for insects. Recent experiments have shown conclusively that 
this is an error, so far as the boll weevil is concerned. 



128 



THE MEXICAN COTTON-BOLL WEEVIL. 



days at 44° to 45° F. made 36 feeding punctures, or at the rate of one 
puncture every 8.4 days. It is probable that these punctures were all 
made possible by the removals from refrigeration for examination. 



LOWER ZONE OF FATAL TEMPERATURES. 



In 1904 Dr. W. E. Hinds conducted experiments in the effects of 
low temperature on eggs and young larvae. He found that 34 eggs at 
45° F. for 13 to 14 days did not hatch when kept later at a temper- 
ature of 69° to 70° F. Recently hatched larvae, however, were killed 
by nine days' exposure to 45° F. 

By experiments conducted with adults in 1905 it was ascertained 
that 32° F. was not fatal; 24° F. benumbed the weevils, but they could 
revive; 18° F. killed. 

In experiments conducted by Mr. H. P. Wood 32 weevils were 
exposed to a minimum of 15° F. and an average temperature of 18.6° 
F. for seven and one-fourth hours and then placed in the refrigerator 
at a higher temperature, but none recovered. 

In similar experiments Mr. W. A. Hooker exposed 11 weevils for 
six hours to temperatures varying from 15° to 20° F. The weevils 
were quiet, but later showed signs of life, although they died within 
two days. Between 7 and 10 degrees, five weevils were killed in six 
hours. One degree below zero was absolutely fatal. 

Observations on the effects of low temperatures upon the weevils in 
the fields leads to the statement that all places experiencing a tem- 
perature under 12° F. in the early part of the winter will profit by an 
almost complete extinction of the weevil, depending somewhat, of 
course, upon the amount of protection the weevils may have secured 
before the freeze. Regions having a normal minimum temperature 
of zero need have little fear of serious continued depredations from 
the weevil until the insect has proved itself able to adapt itself to 
colder temperatures than it is now able to withstand. 

In this connection it will be of interest to submit Table LXI, giving 
the average winter mortality from cold since the beginning of our 
records. 



Table LXI. 



• Weighted average cold control of immature stages of the boll weevil, by 
months. 



Month. 


Forms ex- 
amined. 


Stages 
found. 


Killed by 
cold and 
wetting. 




5,687 
13,597 
2,500 
2,534 
2,663 


1,285 
665 
159 
798 
688 


Per cent. 
36.42 




67.36 




31.44 




41.40 




38.37 






Total 


26,981 


3,595 


44.61 







It should be noticed that winter cold is, on the average, almost twice 
as effective as summer heat. 

The history of the boll weevil furnishes several examples of winter 
control, principal among which are the early freezes of November, 
1907, November, 1908, and December, 1909* which greatly reduced 
weevil damage in large sections. 



NATURAL CONTROL. 



129 



FATAL VARIATIONS OF TEMPERATURE. 



It has long been known that one of the most potent forces in insect 
control is abnormal variation of temperature. Probably no stronger 
illustration of such control could be produced than that afforded by 
the conditions of the winter of 1910-11. 




Fig. 27. — Map showing dates of first killing frost in the area infested by the boll weevil, in the winter 

of 1909-10. (Original.) 




Fig. 28.— Map snowing normal dates of first killing frost in the southern United 8ta1 . I Vfter 
Weather Bureau Bulletin V.) 

On October 29 to 30, 1910, a freeze occurred throughout the cotton 
belt affecting all but a narrow strip of territory along the Gulf coast 
and two small interior areas of Texas, as illustrated by the accom- 
panying map (fig. 27). Another map (fig. 28) is presented to show 
28873°— S. Doc. 305, 62-2 9 



130 



THE MEXICAN COTTON-BOLL WEEVIL. 




Fig. 29.— Map showing minimum temperatures on Octo- 
ber 29 and 30, 1910, the date of the first killing frost in 
Louisiana. (Original.) 



the normal dates of the first killing frosts. Comparison of these two 
maps will show at a glance that the first killing freeze of 1910 was over 
a month earlier than the normal. Such a natural phenomenon is an 
exact equivalent of artificial fall destruction at the same date. The 

temperatures were not fatal 
to the weevils, but were 
such as to force hibernation 
and at the same time cut 
off food supply. If tem- 
peratures compelling hiber- 
nation had continued, the 
weevils would have emergep 
in about the same propor- 
tion as would be expected 
if they were artificially de- 
prived of food on the same 
date. However, another 
climatic factor intervened. 
Almost the entire month 
of November was warm, and 
throughout Louisiana, at 
least, the mean temperature 
stood at above56°F.forthe 
month. We have already 
shown that a continuance 
of mean temperatures over 
56° F. will force the weevils to take food, and that in the absence of food 
at effective temperatures starvation occurs in a few days. If all of 
the cotton had been killed by the freeze, the control would have been 
complete, but there are al- 
ways sheltered areas on 
hillsides or near buildings 
that escape two or three 
severe freezes, and these 
areas no doubt harbored 
many weevils until the 
cold wave of November 29 
drove them to a normal 
hibernation. 

In the map (fig. 29) show- 
ing the Louisiana minimum 
temperatures of October 29 
and 30, 1910, on which 
dates the first killing frost 
occurred, it will be noticed 
that no fatal temperature 
was reached, but that a 
freezing temperature oc- 
curred in practically all of 
the cotton-producing terri- 
tory. The other map (fig. 30) illustrates the minimum temperatures 
of the entire winter of 1910-11 and shows that fatal temperatures 
(7° F. to 22° F.) occurred throughout the State. These minima 




Fig. 30. 



Map showing minimum temperatures in the winter 
of 1910-11 in Louisiana. (Original.) 



NATURAL CONTROL. 131 

occurred, however, early in January, at which time all weevils which 
had survived the starvation of the fall were deeply hidden in hiber- 
nation shelters, where sudden changes of temperature have little 
effect. 

The survival from hibernation at Tallulah, La., was only one-half 
of 1 per cent, as shown in the hibernation statistics, and this, no 
doubt, must be attributed to the rare combination of early freeze, 
subsequent long duration of effective temperatures without food, and 
finally a period of minimum fatal temperatures. 

One of the most interesting features of the fall of 1910 in Texas was 
the presence of two small areas in which the first freeze was delayed 
from one to two months. (Fig. 27.) We call attention to the most 
interesting of these cases. The freeze of October 29 was felt in all 
Texas above the latitude of 31°, except in Erath, part of Comanche, 
part of Brown, Eastland, Callahan, Taylor, Jones, and Haskell Coun- 
ties in central-west Texas. In this frost-free area in the following 
October, 1911, a very heavy infestation was found at Cisco, in East- 
land County, and at Brown wood, in Brown County. The infestation 
diminished in every direction from those places. At Lampasas, 60 
miles southeast of Brownwood, where we would naturally expect a 
much higher infestation than at Cisco, very slight damage occurred, 
and at Granbury, in Hood County, 60 miles east of Cisco, where the 
weevils have been present since 1904, they were extremely difficult 
to find. Thus, it is seen that a territory which had had the weevil 
much longer than either Brownwood or Cisco had fewer weevils in 
1911, because it experienced an earlier killing frost. 

EFFECTS OF FLOODING UPON THE WEEVIL. 

Tests at Victoria, Tex., in 1904, were divided into two parts, each 
of which included both the immature and mature stages. In each 
part floating and submergence were tested. In the tests made upon 
the floating power of adults, weevils were isolated and placed in water 
in tumblers. They were dropped from a considerable distance above 
the surface, so that they became entirely submerged, and they rose 
to the surface naturally. The surface tension of the water was found 
to be sufficient to float weevils which were placed upon it carefully. 
The generally hairy condition of the surface of the weevil's body 
prevents it from being readily wetted, so that it may struggle for 
some time in the water without becoming really wet. When dropped, 
as described above, weevils float head downward, with the tip of the 
abdomen above the surface. In the submergence tests weevils were 
held down by a wire screen, and all bubbles were removed from their 
bodies by a pipette, thus making the tests as severe as possible. 

Sixty squares believed from external examination to be infested 
were floated in a driving rain for six hours. They were then removed 
and left for several days, during which time 75 per cent of them pro- 
duced normal adults. Ten squares which were floated in driving 
rain for six hours were opened at once, and in every case found to be 
only slightly moist on the inside. These contained six larvae and 
four pupa?, and all were in perfect condition. 

As squares float normally, submergence tests were considered 
extreme. Five squares were submerged for six hours, and after that 
produced three normal adults; one pupa died, and one square was found 



132 THE MEXICAN COTTON-BOLL WEEVIL. 

to have been uninfested. Five more squares were submerged for 31 
hours. These produced two normal adults, and one pupa died in the 
process of molting after removal from the square. Death was prob- 
ably caused in the last case by drying; one square was found to contain 
a dead pupa, and one was not infested. To test the possibility of its 
living, should the square be penetrated by water, a naked pupa was 
submerged for six hours, but in spite of this unusual treatment it pro- 
duced a normal adult. Numerous larva? removed from squares and 
placed in water pupated in one or two days, and several pupae 
remained alive, though floating for several days in water before they 
transformed into adults. 

In the case of squares floating normally it is evident that they 
might remain in water for several days without injury to the weevil 
within. Very slight wetting of the cell takes place, even under the 
extreme conditions of submergence. The effect of a brief flood 
would not, therefore, be at all injurious. As adults float as readily 
as do squares, they may also be carried long distances, and, further- 
more, they are able to crawl out of the water upon any bushes, weeds, 
or rubbish which they touch. Even when floating for several days 
continuously they are able to live and may be carried directly to 
new fields. The floating of adults and infested squares explains the 
appearance of weevils in great numbers along high-water lines 
immediately after a flood. 

Field observations were made to supplement the laboratory experi- 
ments recorded in the preceding paragraphs. In July, 1904, many 
fields in the vicinity of Victoria, Tex., were partially and some wholty 
submerged. This condition lasted for several days. Examination 
made after the recession of the water showed that many fallen 
squares which had been in the water for some time contained unin- 
jured larva? and pupa?. Naturally, eggs and larva? found in squares 
upon the plants, even though under water for some time, escaped 
unharmed. Weevils were working normally upon the plants. No 
diminution in their numbers could be seen, and it was apparent that 
the overflow caused no check either to the development of the imma- 
ture stages or to the activity of the adults. 

PLANT CONTROL. 

While climate is the foremost factor in the control of the boll 
weevil and also of the behavior of the cotton plant, there are certain 
kinds of control which the plant itself exerts. One of the most 
important of these is proliferation, which will be discussed in the fol- 
lowing paragraphs. 

PROLIFERATION. 

Early in the investigation of the boll weevil it was noticed that the 
immature stages and sometimes even the adults are frequently 
killed by a form of reaction of the plant known as proliferation. 1 It 
appears that this property of the plant might be emphasized by 
breeders. For this reason special studies were conducted in 1905 

1 Dr. O. F. Cook, of the Bureau of Plant Industry, has published a number of papers in which references 
are made to proliferation. The reader is referred to these papers, which are included in the bibliography 
at the end of this bulletin, for a full discussion of the botanical aspects of the phenomenon. 



NATURAL CONTROL. 133 

and 1906. The results were published in Bulletin 59 of the Bureau 
of Entomology from which the following statements are abstracted. 

For the present purposes proliferation may be defined as the devel- 
opment of numerous cells from the parts of the bud or boll of the 
cotton plant which are injured by the weevil. It is clearly a mani- 
festation of an inherent tendency on the part of the plant to counter- 
act irritation by the growth of large numbers of new cells. This 
growth usually begins in the layer of cells adjoining the lining of the 
boll or in the stamina! column of the undeveloped bloom. Part of 
the formation may project through the rupture made by the weevil 
or may form a hemispherical mass protruding from the inner side of 
the carpel of the boll and pressing into the lock. The react ion on the 
part of the plant begins generally before the egg hatches. In some 
cases the egg itself may be moved a considerable distance by the 
growth. In other instances the egg becomes enveloped and the larva 
emerges in the proliferous mass. Under such circumstances it may 
be destroyed early in life, although it often makes its way through 
the mass into portions of the fruit which have not been affected. As 
the larva feeds it continues and increases the irritation, and the 
response of the plant is immediate. In this way it often happens 
that the space the larva has eaten out becomes filled by the proliferous 
mass, and the pressure becomes so strong that eventually the larva 
or the resulting pupa or adult is crushed. It is clear from the observa- 
tions made that it is this crushing effect that destroys the weevil. 
(See PI. XIV, b.) A number of experiments in which weevil larvae 
were placed in proliferous tissues showed that they could develop 
normally upon this modification of their natural food. 

The frequency of the occurrence of proliferation was determined by 
the examination of 1,870 squares and 2,042 bolls of a large number 
of American and several foreign cottons. In the case of squares, it 
was found that in the averages for all seasons and localities proliferous 
growth followed feeding punctures in 48 per cent of the cases. The 
highest percentage, 75, was in the case of the Jannovitch, an Egyptian 
variety. In the case of bolls, proliferation followed in SI per cent of 
the cases of feeding punctures. It is consequently apparent that 
proliferation occurs more frequently as a result of feeding punctures 
m bolls than in the case of punctures in squares. 

No very satisfactory results followed a study of the effect of climatic 
conditions upon the frequency with which proliferation follows the 
attack of the weevil. The observations included a number of 
varieties growing in two localities during two seasons, but there seems 
to be no special relation between the locality and the season and the 
number of cases in which proliferation was found. In fact, the 
maximum percentage of formation of proliferation in bolls and the 
minimum in squares occurred at the same time in the same locality 
and with the same variety. 

Table LXII shows the weevil mortality due to proliferation in 
squares and bolls under natural conditions. 



134 



THE MEXICAN COTTON-BOLL WEEVIL. 



Table LXII. — Summary of observations showing increased mortality of the boll weevil 
in squares and bolls caused by proliferation. 1 





•6 

0J> 
> 

o 
o 

3 
o 
o 


oj 

-a 
a 

a 
.2 

03 

> 


Squares examined. 


Mortality 
in squares. 


>> . 
£ c 

3.2 

o 2 

.as 

Is 
II 


•6 

.9 

2 

03 

y, 

o 

P5 


Locks examined. 


Mortality 
in locks. 


II 


Years of 
observa- 
tions. 


o 
$ 

B 
3 

a 

3 

O 

■— 


ii 

M% 


II 

fit 
3353 

o — 

feg 


ft.2 

£1 03 


6 

ftd 
o 

P 


a 

_ X! 

03 
O 


5o 

• r o 
03 

CO 


■Sd 

,? ft 
ft " 


ft-2 
si 03 



t- . 

ftc 

■*>.2 

2 


Eg 
S3 

£ 3 
C-3 


1902 


4 
1 
1 
1 
2 
1 
1 
1 
1 
1 
1 


4 
1 
1 

9 
2 

14 
6 
1 
4 

14 
1 


105 


44 


41.9 


P.ct. 
30.5 


P.rt. 

19.5 


P.rf. 

11.0 










P.tf. 


P.rt. 


P.rf. 


1903 


240 
452 


1,033 
1,898 


434 
995 


42.0 
52.4 


15.0 
28.4 


5.0 
12.8 


10.0 
15.6 


1903 














1904 


2, 954 


1,480 


50.0 


9.0 


.6 


9.0 


1904 


398 


1,708 


8S5 


51.8 


18.2 


11.1 


7 1 


1905 


4.504 
771 
443 
144 


2,305 
372 
212 

40 


52.5 
48.2 
47.9 
27.8 


19.6 
28.6 
25.1 
34.8 


5.5 

.3 

9.7 

3.2 


14.1 

28.3 
15.4 
31.6 




1905 
















1905 
















1905 
















1905 


1,802 
82 


7,821 

254 


5,069 
158 


64.8 
62.2 


16. 7 

14.6 


8.5 
.0 


8 2 


1905 














14.6 
















Totals 
and av- 






8,921 


4,513 


2 50. 6 


2 17.2 


2 3.7 


2 13.5 


2,980 


12.714 


7,541 


2 59.3 


2 15. 5 


2 9.2 


2 3 















1 From Bulletin 59. Bureau of Entomology, p. 27. 



2 Weighted average. 



It will be seen that in the case of squares there was a range of from 
9 to 31 per cent increase in the mortality due to proliferation, the 

feneral average being 13 per cent. In bolls the range is not so great, 
eing only from 7 to 15 per cent, while the average increase in mor- 
tality in bolls was found to be 6 per cent. This is slightly less than 
one-half as great a mortality as was found to be the case in squares. 
A number of interesting experiments were performed to determine 
whether artificial punctures were as frequently followed by prolifer- 
ation as those made by the weevil. One thousand one hundred and 
three needle punctures were made, resulting in proliferation in 36 per 
cent of the cases. This percentage is not so large as in the case of feed- 
ing punctures of the weevil, but it is as large as could be expected when 
the difference between a clean needle puncture and the rough, lacerating 
puncture by the weevil is considered. It consequently appears that 
it is the mechanical injury of the weevil rather than any secretion 
which causes the growth. A further series of experiments showed 
that injections of caustic potash, formic acid, and other chemicals did 
not appear to increase the number of cases in which proliferation 
followed. It did appear, however, that unsealed artificial punctures 
resulted in more frequent proliferations than sealed punctures of the 
same kind. 

A number of experiments were instituted to show the possible 
effect of heavy fertilization of the cotton plant upon its tendency to 
form proliferous tissues. It was supposed that some such cultural 
expedient as fertilization might increase the resistance on the part of 
the plant. In the case of over 8,000 observations made on fertilized 
cotton growing in two localities, however, it was found that prolifer- 
ation followed attack by the weevil practically as frequently in the 
one case as in the other. Squares on fertilized plats showed prolifer- 
ation in 50.5 per cent of the cases; on unfertilized plats in 49.5 per 



NATURAL CONTROL. 135 

cent. Bolls on fertilized plats showed proliferation in 66.2 per cent of 
the infested locks; on unfertilized plats in 69.5 per cent. 

It was found that proliferation very frequently follows the attacks 
of any of the insects which injure the cotton boll or square. In the 
case of these other insects the phenomenon is of little importance, 
since, unlike the weevil, they generally make punctures merely for 
the purpose of feeding. The immature stages are not developed in 
the cotton fruit and are consequently beyond the reach of the growth 
which the adults have incited. 

OTHER PHASES OF PLANT CONTROL. 

There are other forms of plant control wluch require attention. 
Dr. (). F. Cook, of the Bureau of Plant Industry, has been the prin- 
cipal student of this matter and has called attention to numerous 
weevil-resisting adaptations of the cotton plant, although important 
contributions have been made by several other investigators. Among 
the more important properties or tendencies of the cotton plant which 
affect the weevil adversely are: (1) Early bearing, (2) determinate 
growth, (3) hairy stalks and stems (PI. XIV, a), (4) abundance of 
secretion from nectaries, (5) pendent bolls, (6) involucral bracts 
grown together at base, (7) thick-walled bolls, and (8) tendency to 
retain infested fruit (PI. XV). 

Early bearing enables the plant to produce its fruit before the 
weevils have become numerous. In other words, it allows the plant 
to take advantage of the small number of weevils which succeed in 
passing the winter and also to take advantage of the comparatively 
slow development of the insect during the early portion of the growing 
season. 

Determinate growth prevents the maturity of numerous weevils in 
the fall. Plants with this character well marked discontinue both 
growth and fruiting. As the capacity of the weevil to increase is 
limited very largely by the amount of fruit available, it is evident 
that a variety which discontinues fruiting at an early date in the fall 
must reduce greatly the number of weevils that are present to go into 
winter quarters. 

It has been found that the presence of a considerable growth of hair 
on the stalks and stems presents an important obstacle to the progress 
of the weevil and consequently reduces the daily capacity of damage 
of each insect. In some of the American upland varieties, notably 
the King, this hairiness is developed to such an extent as to be a 
form of protection of considerable importance. 

As has been pointed out in another section of this bulletin, boll- 
weevil parasites in the adult stage feed upon the nectar which is 
secreted by the cotton plant. Consequently the greater the secretion 
of nectar the more favorable will be the conditions for these important 
enemies of the weevil. 

There is a more or less constant tendency on the part of the adult 
weevil to frequent the upper portion of the cotton plant. If it hap- 
pens to alight upon a lateral branch which has bolls or squares stand- 
ing upright, attack follows immediately. On the other hand, if the 
branch upon which the weevil alights has bolls which turn downward, 
there is a considerable likelihood that it will work upward to other 
lateral branches and overlook the fruit upon the first branch. 



136 THE MEXICAN COTTON-BOLL WEEVIL. 

The weevil has frequently been observed to experience considerable 
difficulty in reaching the cotton square through the involucral bracts. 
If these bracts are united at the Dase, or very closely appressed, or 
have their edges provided with strong hairs, the natural difficulty the 
weevil experiences will be increased. 

Dr. Cook has pointed out that certain Central American strains of 
cotton have bolls provided with thick interior walls, which in some 
cases the weevil is unable to penetrate. 

As has been pointed out in another section, the insect enemies of the 
boll weevil find the infested squares which remain on the plants more 
suitable for attack, and are able to raise the average control above 
that in fallen squares in most sections. Consequently it is of advan- 
tage to the planter to have a variety with a well-marked tendency to 
retain the infested fruit. The ability to retain the infested squares 
is explained under the heading of parasite attack (p. 144). 

Several other peculiarities of the cotton plant which Dr. Cook has 
interpreted as weevil-resisting adaptations are described in Bulletin 
88 of the Bureau of Plant Industry of this department. 

DISEASES. 

Little attention has been given to the study of diseases of the boll 
weevil because the observations upon the mortality of the insect have 
not indicated any great amount of death due to causes which could 
not be well explained under the headings of climatic, plant, parasitic, 
and predatory control. There is no doubt that bacterial and fungous 
diseases sometimes attack the weevils, especially those hibernating 
in moist places. Only two definite records are at hand of death by 
fungus, and these have been recorded in former bulletins. One was 
a case of a new species of Aspergillus and the other of a species of 
Cordyceps. 

PARASITIC AND PREDATORY INSECT ENEMIES. 

Recent work has added very greatly to our knowledge of the insect 
enemies of the boll weevil. Much remains to be done, however, 
since it has been found that the boll weevil is accumulating species 
after species of parasites as it advances farther into the United States. 
A recent publication of this bureau (Bulletin No. 100) has dealt 
rather extensively with the insect enemies of the boll weevil. In the 
present publication, therefore, only a few of the more important facts 
learned will be considered. 

A BRIEF SUMMARY OF THE INSECT SPECIES ATTACKING THE BOLL 

WEEVIL. 

At the present time the boll weevil is known to be the host of 29 
species of parasites, of which 4 are mites, 21 belong to the order 
Hymenoptera, and 5 are parasitic flies. In addition to these true 
parasites, there are 6 predators which kill the adult boll weevils and 
22 predators which attack the immature stages. These include a 
mantis, a predatory bug, 8 beetles, a leaf-feeding caterpillar, and 17 
species of ants. In all, the boll weevil is known to have 58 species 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XV. 





NATURAL CONTROL. 137 

of insect enemies, and probably many more species will be found as 
the weevil enters new regions. In fact, records of parasite and ant 
attack have been found as early as two weeks after invasion of new 
territory. 

ARACHNIDA. ACARINA. SARCOPTOIDEA. 

Pedicvloides ventricosus Newport. — This mite has been prominent 
in the study of the boll weevil since its first notice (Rangel, 1901) 
under the name of Pediculoides ventriculosns. These mites reproduce 
\ iviparously, and their offspring are mature and fertile at birth. 
After attachment to a host the abdomen begins to inflate until it 
becomes many times greater than the thorax. The time required 
for engorgement varies from two to five days. An average of 100 
female offspring to an individual has been recorded. 

Pediculoides n. sp. — This mite was discovered in the laboratory at 
Dallas, Tex., June 13, 1907, by the junior writer. Observations con- 
tinued for some time proved that there was a generation about every 
four days. The mite has been found attacking several other species 
of weevils as well as many other insects. 

Tyroglyphus breviceps Banks. — This species has been recorded as 
an enemy of the boll weevil from Victoria, Tex. A similar mite has 
also been found at Calvert, Tex. 

GAMASOIDEA. 

Macrocheles n. sp. — Mr. Harry Pinkus found this mite very com- 
mon in the fallen cotton squares at Tullulah, La., during August, 
1911, feeding upon the boll-weevil stages. It has not been definitely 
proved that the species kills the weevil, but the evidence is more or 
less conclusive. 

INSECTA. ORTHOPTERA. MANTID.E. 

Stagmomanfis limbata Halm. — This insect has been found to prey 
upon the adult boll weevil in Texas. 

HETEROPTERA. REDUVIID^E. 

Apiomerus sj>issipes Say. — This predatory bug has been recorded 
by Mr. A. C. Morgan as an enemy of the adult boll weevil in Texas. 

COLEOPTERA. CARABID.E. 

Evartltrvs sodalis LeConte. — This species (fig. 31) is a predator 
upon the adult boll weevil in Louisiana and Texas. 

Evarthrus sp. — Another species of the genus has been recorded by 
Newell and Trehearne as predatory upon adult boll weevils at Baton 
Rouge, La. 

CANTHARHVE. 

Chavliog net thus spp. (see fig. 32). — The larvae of these beetles are 
very common in the squares and bolls of cotton in Louisiana and 
Mississippi. In one instance undoubted proof of the attack of such 
a larva upon a boll-weevil larva was recorded. 



138 



THE MEXICAN COTTON-BOLL WEEVIL. 



Hydnocera pallipennis Say. — A single beetle of this species was 
reared April 6, 1907, from the boll weevil, collected August 28, 1906, 
at Waco, Tex. 





Fig. ZX.—Evarthrus sodalis, an enemy of 
the boll weevil. (Original.) 



Fig. 32. — ChauUognathus marginatus, an ene- 
my of the boll weevil. (Original.) 



Hydnocera pubescens Le Conte (fig. 33). — This is a very common 
breeder in the weevil cells. Its larvae have been not only found feed- 
ing upon the various weevil stages, but have been frequently observed 
feeding upon the parasites of the weevil. 



CUCUJID^E. 



Cathartus gemellatus Duval. — This beetle is a predator and scaven- 
ger, its larvae being frequently found feeding upon boll-weevil stages 
which they must have killed. 



TENEBRIONID.K. 



Opatrinus notus Say. — This beetle has been found by Mr. Harry 
Pinkus at Tallulah, La., to prey as an adult upon the immature stages 
of the weevil in fallen squares during July. It occurred very com- 
monly in the cotton fields. 



LEPIDOPTERA. NOCTUID.E. 



Alabama aryillacea Hiibner. — For many years the ravages of the 
cotton leaf worm attracted almost as much attention in some portions 
of the South as does the damage by the boll weevil now. Various 
changes in the system of cultivation of cotton in the South have 
combined to reduce the damage done by this pest, and, moreover, a 
veiy effective method of controlling it, by the use of Paris green, was 
discovered. It is one of the striking occurrences in the history of 
economic entomology that this formerly dreaded pest is now looked 
upon by the farmers in weevil-infested regions as decidedly beneficial. 




NATURAL CONTROL. 139 

When the plants become defoliated by the leaf worms the growth is 
checked, and consequently the opportunities for the breeding of the 
weevils in additional squares are reduced. This results in a marked 
decrease in the number of weevils at the end of the season. This 
decrease has not so much effect upon the crop of the current year as 
upon the following one by reason of the lessened number of weevils 
that pass through hibernation. Moreover, when the plants have been 
deprived of most of their leaves the worms very frequently devour 
the squares and sometimes small bolls in which the immature stages 
of the boll weevil are located. In this way the leaf worm acts directly 
as a remedial agenc}^ against the boll weevil. This work to some 
extent accomplishes the same result as the fall destruction of the 
plants, which, as is well known, is the greatest 
single factor in the successful production of 
cotton in weevil-infested regions. There is still 
another consideration in this connection, 
namely, that the defoliation of the plants allows 
the sun to strike the squares upon the ground. 
thus destroying many of the larva? and pupae of 
the weevil contained therein. At the present 
time, as the result of the conditions mentioned, 
the planters in the infested regions are rapidly 
giving up the practice of poisoning the formerly 
much dreaded caterpillar. If, as may occa- 
sionally happen, the plants become defoliated 
before the weevils reach the maximum numbers 
in the fields, the damage of the one insect will fig. zz.~Hydnoccra pubescens, 
simply be added to the damage of the other. In ^3° f the bo11 "^ 
that event the use of poison will be necessary. 1 

In the extensive defoliation by the leaf worm in 1911 one of the 
most striking features was the scattering of the boll weevil for great 
distances into new territory. The general absence of green fields 
caused the weevils to fly much farther than they would otherwise 
have done. 

HYMENOPTERA. FORMICOIDEA. DORYLID^E. 

Eciton (Acamatus) commutatus Emery (PI. XVI, a). — This ant has 
been observed only once, at Beeville, Tex., attacking the weevil 
larvae in squares. 

PONERID.E. 

Ectatomma tuberculatum Olivier. — The ''kelep," or so-called Guate- 
malan ant, is a native of Mexico and Central America. Like all other 
ponerids, it is slow in action, but is able to capture such weevils as 
come within its reach on the cotton plants. Numerous attempts to 
establish this species in the United States have failed. 

MYRMICID^E. 

Cremastogaster lineolata Say, subsp. Jseviuscula Mayr, var. clara 
M;ivr. (PI. XVI, b). — This ant, although normally a honeydew feeding 
species, is also an enemy of the immature stages of the boll weevil in 
Texas. 

Solenopsis geminata Fabricius, var. diabola Wheeler. — The common 
fire ant of the Southern States is one of the best enemies of the boll 

*^7 he al >9 ve paragraph is from W. D. Hunter in the Yearbook of the Department of Agriculture for 
1904, p. 201. 



140 THE MEXICAN COTTON-BOLL WEEVIL. 

weevil, being very industrious in its search for infested squares, which 
it enters in great numbers. 

Solenopsis molesta Say (PL' XVI, e). — This minute ant was taken 
in the act of attacking a boll-weevil larva at McAlester, Okla., by Mr. 
R. A. Cushman. 

Solenopsis texana Emery. — This ant is a common enemy of the 
immature stages of the boll weevil in Texas, Louisiana, and Missis- 
sippi. 

Monomorium minimum Buckley. — The common house ant is a 
very valuable enemy of the boll weevil in Texas, Louisiana, and Mis- 
sissippi. 

Monomorium, pharaonis Linnaeus (PL XVI, d). — This cosmopolitan 
house ant is another of the more important boll-weevil enemies in 
Texas, Louisiana, and Arkansas. 

Pheidole sp. near Jlavens. — This species was found abundantly 
attacking the immature stages of the boll weevil at Arlington, Tex., 
August 31, 1908, by Mr. R. A. Cushman. 

Pheidole crassieornis Emery. — This species was found as an abun- 
dant enemy of the immature stages of the weevil at Lampasas, Tex., 
September 23, 1908, by Mr. R. A. Cushman. 

DOLICHODERID.E. 

Forelius maccooki Forel. — This ant has been recorded at several 
places in Texas as an enemy of the immature stages of the boll weevil. 

Dorymyrmex pyramicus Roger (PL XVI, c). — The so-called lion ant 
of Cuba was recorded by Mr. E. A. Schwarz (1905) as protecting 
solitary tree cotton from the boll weevil. 

Dorymyrmex pyramicus Roger, var. jlavus Pergande. — This com- 
mon cotton-field ant has only once been recorded definitely as an 
enemy of the boll weevil. This record is from Texarkana, Tex., by 
Mr. R. C. Howell. 

Iridomyrmex analis Ern. Andre. (PL XVI, /). — This common ant is 
normally a honey-loving species, but occasionally attacks insect food. 
It has been found attacking the boll weevil by Dr. W. E. Hinds. 

Iridomyrmex humilis Mayr. — The Argentine ant has formerly been 
recorded as an enemy of Solenopsis geminata, Monomorium pharaonis, 
and Iridomyrmex analis, three of our common boll-weevil enemies. 
Mr. T. C. Barber has recently reported that the Argentine ant, by 
continually worrying the boll weevils and killing newly emerged 
adults, practically cleared a heavily infested cotton patch at Baton 
Rouge, La., in September, 1909, at a time when fields outside of the 
ant territory were still very seriously infested. 

FORMICID.E. 

Formica subpolita Mayr, var. perpilosa Wheeler.— This species is 
normally a honey feeder, but has been recorded by Rangel (1901) as 
a predator upon adult weevils in Mexico. 

Formica pallidi-fulva Latreille. — A single instance of this species 
cutting its way into a boll weevil-infested square was observed by 
Mr. C. E. Hood at Ashdown, Ark., September 2, 1908. The species 
is commonly found on the cotton plants. 

Prt nolepis imparis Say. — Mr. C. E. Hood recorded this species as 
an enemy of the immature stages of the boll weevil at Ashdown, 
Ark., September 2, 1908. 



Bui. 1 14, Bureau of Entomology. U. S. Dept. of Agriculture. 



Plate XVI. 






Boll-Weevil Ants. 

a, Eciton eommutatm; b, Cremagtogaster lineolata; c, Dorymyrmex pyramicusj </, Monomorium 
pharaonis; >. SolenopsU molesta; f, Iridomyrmex analu. [Original.) 



Bui. 1 14, Bjreau o* Entomology, U. S. Dept. of Agriculture. 



Plate XVI 




Boll-Weevil Parasites. 



,i, Eurytoma tylodermatis, male; b, Eurytoma tylodermatis female; c, Microdontomerus 
anttumomi, female; <■'. antenna of same; d, Habrobytua piercci, female; <!', antenna of 
same; e, Catofumm litmU ri, lViuale; <', antenna of same; /.antenna of Catolaccus incer- 

tus, (Original ) 



NATURAL CONTROL. 141 

HYMENOPTERA. CHALCIDOIDEA. CHALCIDIDjE. 

Spilochalcis so. — A single male of this species was found dead in a 
weevil cell with the remains of the weevil and its own exuvium 
August 10, 1907, at Victoria, Tex. 

TORYMID.E. 

Microdontomerus anthonomi Crawford (PI. XVII, c). — This is one 
of the most important parasites of the boll weevil in Texas and 
Louisiana. It is generally found throughout the year and is known 
to attack two other species of weevils. 

kckytomiii.e. 

Eurytoma tylodermatis Ashmead (PI. XVII, a, b). — This species 
ranks among the five most important boll-weevil parasites, and its 
range is practically coextensive with that of its host. It is known 
to attack 14 other species of weevils. 

Euryt oma sp. — Two species of this genus were reared from hanging 
squares collected August 10, 1907. at Victoria, Tex. 

Bruchovkcigus herrerse Ashmead.- This parasite has been recorded 
from the boll weevil from Mexico, but the name is thought to be a 
synonym of Eurytoma tylodermatis. 

PERILAMPIIhK. 

Perilampus sp. — A single individual was reared from the boll 
weevil by isolation from material collected September 7, 1907, at 
Shreveport, La., by Mr. C. E. Hood. Considerable doubt has been 
raised concerning this record by authorities upon the breeding habits 
of Perilampidse. 

ENCYRTID.E. 

Cerambycobius cyaniceps Ashmead (PI. XVIII, /). — The range of 
this species is coextensive with the boll weevil in the United States. 
It is extremely important in northern Louisiana and Arkansas, and 
is known to attack 17 species of weevils. 

Cerambycobius cushmani Crawford. — This species is evidently 
limited to southern Texas, where it is occasionally important. It is 
known as a parasite of four other species of weevils. 

^ ( 'erambycobius sp.— On February 23, 1909, a male of a green species 
of this genus was reared from a weevil in squares collected at Natchez, 
Miss., on January 19. 

PTEROMALIDvE. 

Catolaccus hunteri Crawford (PI. XVII, e). — This is one of the most 
important parasites of the boll weevil. It is of greatest importance 
in Louisiana and Mississippi. Twelve other species of weevils are 
known as hosts. 

Catolaccus incertus Ashmead (PI. XVII, /"')• — This is also a very 
important species and occurs throughout the infested region. It is 
also a parasite of 13 other species of weevils. 

Habrocytus piercei Crawford (PI. XVII, d). — This brilliant green 
parasite has been reared from the boll weevil only in the fall and 
winter months in Louisiana ami Texas. One other weevil host is 
known. 



142 THE MEXICAN COTTON-BOLL WEEVIL. 

Lariophagus texanus Crawford (PI. XVIII, a). — There is strong 
evidence that this species is a primary parasite of the boll weevil in 
southern Texas. It is also undoubtedly a parasite of four other 
species of weevils. 

EULOPHID.E. 

Tetrastichus Tiunteri Crawford (PI. XVIII, b, c). — This parasite of 
the boll weevil has been known only since 1908. It is the only 
internal hymenopterous parasite of the weevil and occurs commonly 
in Louisiana and Mississippi and has been recorded from Texas. It 
is evidently more important in the fall of the year. 

ICHXEUMOXIDEA. ICHXELMOXID.E. 

Pimpla sp. — On February 23, 1909, a single female of this species 
was reared from a weevil larva collected at Nacogdoches, Tex., on 
January 27. 

BRACOXIDJE. 

Sigalphus curculionis Fitch. — This common parasite of the plum 
curculio has been found frequently attacking the boll weevil in 
Louisiana and Mississippi. It is known as a parasite of eight other 
species of weevils. 

Urosigalplius anthonomi Crawford. — This species has been reared 
from the boll weevil only at Brownsville, Tex. 

Urosigalplius schwarzi Crawford. — This species is a parasite of the 
boll weevil in Guatemala and has never been reared in the United 
States. 

Urosigalplius sp. — A single specimen of this species was reared in 
1909 at Arlington, Tex. 

Microbracon mellitor Say.— Until 1909 this was the most important 
parasite of the boll weevil. It is coextensive in distribution with its 
host, but is by far most important in Texas and Oklahoma. It is 
known as a parasite of 10 other species of weevils. 

An unknown braconid, nearly related to Glyptocolastes, was reared 
from the boll weevil in southern Texas. 

DIPTERA. PHORID.E. 

Aplxiochsda nigriceps Loew. 

Aphiochseta fasciata Fallen. 

Apliiocliseta pygmsea Zetterstedt. 

These three species and also possibly others in this genus have fre- 
quently been found feeding upon boll-weevil larvae and in many cases 
under such circumstances that they must be assumed to be parasites 
as well as scavengers. 

TACHIXID.E. 

Myiophasia senea Wiedemann. — This fly has been recorded as a 
parasite of the boll weevil in Texas. It is also an enemy of six other 
species of weevils. 

Ennyomma globosa Townsend (PI. XVIII, d, e). — This fly is an 
important parasite of the boll weevil in Louisiana. It also attacks 
the cowpea curculio. 



NATURAL CONTROL. 143 

Careful studies have proved that the 29 species of parasites are all 
derived from native hosts, which are mainly weevils breeding in 
weeds and other plants growing normally around the cotton fields. 
Some of these parasites have lived for many generations on certain 
common weevils until suddenly some abnormal condition has deci- 
mated the numbers of the normal hosts or freed the parasites of their 
normal control, thus upsetting the natural equilibrium between them 
and their hosts. In this way the parasites have been compelled to 
seek new hosts, and the presence of the boll weevil in large numbers 
has led them to attack it. This has been demonstrated by the 
sudden adaptation of several species of parasites at Victoria, Tex. 
These were normally enemies of the huisache pod weevil, but were 
unable to attack this insect in 1907 because of the failure of the hui- 
sache trees to fruit. Another demonstration of sudden adaptation 
was found in the sudden increase of attack by Eurytoma tykaermatis 
following the cutting of a number of weeds in which this parasite was 
attacking a native weevil. Such adaptability of course suggests the 
advisability of keeping the weeds in the vicinity of cotton fields cut 
down during the summer in order to force the parasites to attack the 
boll weevil. 

After a parasite has once attacked a new host it becomes com- 
paratively easy for succeeding generations to repeat the attack. In 
this manner many species of weevil parasites have increased their 
range of hosts until they have obtained a complete series extending 
throughout the }'ear. A rotation of hosts has, therefore, been estab- 
lished. As many as f7 different wee\ils are attacked by one of the 
species of boll-weevil parasites. To illustrate the value of this rota- 
tion we have but to quote one of the commonest examples. The 
strawberry and blackberry bud weevil is very common in the South 
in the 1 latter half of March and until June. Two of the species of the 
boll-weevil parasites attack this weevil as soon as it begins to breed, 
and they are able to develop at least one generation before the boll 
weevil can begin its attack on the cotton squares. These parasites 
are found attacking the boll weevil throughout the summer. In the 
fall they begin to attack certain stem weevils, such as the potato 
or Solanum stem weevils, and produce a generation during the winter 
which emerges in time to attack the strawberry weevil. Thus, two 
generations are developed while the boll weevil is in hibernation. To 
obtain a practical benefit from this rotation of hosts it is only neces- 
sary to have a hedge of dewberries or blackberries along the fences. 

It is of extreme importance to know that no matter what exigencies 
reduce the boll weevils, the parasites, though also reduced in numbers, 
will still be conserved on their native hosts and will attack the boll 
weevils again as soon as they become sufficiently numerous. 

The location of the developing stages of the weevil is of much 
importance to the insect enemies. (See PI. XV.) It has been found 
that cotton varieties display two distinct tendencies in their response 
to injury to their fruit. Certain varieties, such as King, Simpkins, 
and Shine, are distinguished by a transverse ring at the base of the 
pedicel of the square and bolL When the square or boll is badly 
injured, the plant immediately cuts off circulation by forming a 
corky layer at this ring, and the injured member falls to the ground. 
Other varieties, such as Dickson, Rublee, and in general the cluster 



144 



THE MEXICAN COTTON-BOLL WEEVIL. 



anil semicluster types, are distinguished by an elliptical mark which 
encircles the pedicel, but extends down the stem for one-half to a 
whole inch or more, and is usually incomplete at the lower end. 
When such a square is injured, the corky layer is of course diagonal, 
extending downward on the stem, but usually incomplete, so that 
the injured member adheres by a thread of bark ancl dries on the 
plant. A very extended series of observations has definitely proved 
that the hanging dry infested square is the most favorable place for 
parasitic control and that the total control of the weevil by all causes 
increases in proportion to the number of these hanging dry infested 
squares. A proper selection of varieties is, therefore, a practical 
method of increasing control. 

On the other hand, it must be understood that insect control of the 
stages in fallen squares is often very high. Certain parasites and all 
of the ants and predatory beetles are more likely to find the immature 
weevils in the soft moistened or dried fallen squares than in the diy 
hanging squares. Thus the developing weevil has enemies wherever 
it is. The parasite control on the ground will be obtained best by 
the methods of cultivation to be mentioned hereafter. 

The adjustment of new species of parasites and predators in each 
new region makes it apparent that the boll weevil will everywhere 
be attacked by those species of insects most fitted to attack it under 
the existing local conditions. This attack will be of greatest impor- 
tance in regions where humidity tends to reduce the effectiveness of 
other forms of control. 

By Table LXIII we show the final summary of the records of para- 
sitism made for a period of years to illustrate the fact that this is a 
factor of great importance. 

Table LXIII. — Parasite control of the boll weevil, by years. 



Year. 


Weevil 
stages. 


Parasites. 


Mortality 

from 
parasites. 


1002 


602 

819 

1,005 

1.702 

40, 073 

13,602 

29,349 

11,653 


59 

32 

21 

1,728 

1,121 

2,952 

620 


Per cent. 
1.16 


1903 


7.20 


1(M)">, March 


3.18 


1905, \ugust 


1.23 


1906 


4.31 


1907 


8.24 


1908 


10.05 


1909 


5.32 








98, 805 


6,540 


6.61 







Table LXIII is based upon collections of squares and bolls made 
throughout the infested territory under a great diversity of conditions. 

The average monthly parasitic and predatory control for the years 
1906 to 1909, inclusive, has been arranged below (Table LXIV) to 
show that insects are a factor of importance throughout the year. It 
should be noted especially that in the months of August and Septem- 
ber, when the boll weevils are most numerous, from 27 to 30 per cent 
of the immature stages are killed by insect enemies. The average 
for the year of 25 per cent offers great encouragement. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XVIII. 






Boll-Weevil Parasites. 



a, Lariophagus tetanus, female; b, emergence hole of Tetrastichus hunten from weevil larva; 
<■. Trtmxti'eltttx hunt: ri, female: >•', antenna of same: </, puparium of Ennyomma gldbosain 
weevil larva: e, Ennyomma globosa; f, Oerambycobius cyaniceps, female; /', natural position 
ol same. (( Original.) 



NATURAL CONTROL. 



145 



Table LXIV. — Weighted average insect control of immature stages of the boll weei il, by 

months. 



Month. 



Forms ex- 
amined 



Stages 
found . 



Killed 

by par- 
asites. 



Per- 
centage 

killed 
by par- 
asites. 



Killed 

by 

preda- 
tors. 



Per- 
centage 
killed 

by 
preda- 
tors. 



Per- 
cent ace 
killed 
by all 
insects. 



January... 
February. . 

March 

May 

June 

July 

August 

September. 
October. . . 
November. 
December . 



Total 

Weighted average. 



5,087 
13,597 

2,500 
100 
16,930 
43, 059 
80,923 
37,378 
17,344 

2,534 

2,663 



,285 
665 
159 
56 
,708 
,758 
,170 
,107 
,283 
798 



54 

56 

2 

2 

553 

536 

,970 

,160 

879 

127 



63 
60 

28 


'.IV i 

247 
248 

495 

77:: 
2 
14 



4.90 

9.02 
17.61 
.00 
18.57 
1 4. 92 
24 86 
20. 43 

9.33 
.25 

2.03 



9. 10 

17.44 
18.86 
3. 57 
23. 73 
21.97 
30.79 
27. 21 
19.94 
16. 16 
13. 94 



222, 715 



94, 677 



17,919 



6.78 



18. 92 



The weighted average insect control in June, July, August, and September proves to be 26.82 per cent 
and for the remainder of the year 17.11 per cent. 

A few records of high insect control will suffice to illustrate the 
extent of control under some conditions. 

Table LXV. — Highest records of insect control of the boll weevil. 



Date. 



Location of 
squares. 



Stages. 



Killed by 
insects. 



Athens, Tex 

Hallettsville, Tex 

Overton, Tex 

Athens, Tex 

Beeville, Tex 

Victoria, Tex 

Beeville, Tex 

Arlington, Tex.. . 
Cuero, Tex 



Aug. 
Aug. 
Aug. 
Aug. 
Aug. 



1,1907 
1,1908 
1,1906 
1,1907 
1,1906 



July 29,1908 
Sept. 1,1906 
July —,1909 
June 20,1908 



Fallen... 
..do.... 
..do.... 
Hanging 
Fallen.. 
..do.... 
..do.... 
Hanging 
Fallen... 



255 

100 

197 

75 

1,310 

375 

678 

55 

549 



Per cent. 
96.11 
92. 00 
85.20 
84.00 
78.80 
78.38 
77.40 
75.44 
73.60 



The distribution of insect control in the four principal classes of 
forms, and also by geographical sections, has been presented in the 
general discussion of natural control. 

BIRDS. 

Exhaustive studies of the stomachs of many birds killed in infested 
cotton fields by the agents of the Biological Survey of this depart- 
ment have emphasized the fact that the birds play a considerable 
part in the control of the adult boll weevils. This investigation has 
resulted in a list of 53 species which more or less commonly feed upon 
the adult weevils. In Cuba, Mr. E. A. Schwarz discovered that an 
oriole (Icterus hypomelas) has developed a habit of extracting the 
immature stages from the bolls and squares. 

Table LXVI, which follows, is taken from Circular 64 of the Bureau 
of Biological Survev. 



28873°— S. Doc. 305, 62-2- 



-10 



146 



THE MEXICAN COTTON-BOLL WEEVIL. 



Table LXVI. — Schedule of stomach examinations of birds which had eaten boll weevils. 





During Janu- 
ary, Febru- 
ary, and 
March. 


During ' During July, 
April, May, August, and 
and June. September. 


During Octo- 
ber, Novem- 
ber, and 
December. 


Species. 


•3 

u 

o a 

si 

S a; 
3 


O0 

9 

<v 

O > 

So 


is 

o| 

•r — 

9 : 
3 9 


CO 

•0 
•fci . 

o.g 
fe9 

11 
3 


6J0 

.9 

ail 


Id 

1* 


•3 
.3 . 

9 
fe9 

G :- 
3 
55 


be 

a 

QJ [> 

o> 
a> 

9"3 
3"° 


Id 

<v 

XI !> 

C ai 


-9 

•a . 

— & 

a 

& i 

9 -- 
3 


a; ? 
3-° 






48 
28 
63 






13 

l 

10 


1 


1 


1 

6 

38 

10 

91 

22 

5 

2 

2 

3 

14 

1 

84 

11 

1 














2 


5 






1 
108 
















1 


l 












4 
5 

6 
1 
1 
1 
1 
7 


15 
7 
8 
3 
1 
2 
2 

21 
































10 

7 


1 
1 


1 
2 
























19 






13 


3 


3 


























































8 
92 
79 
48 
52 


1 
4 
4 
10 
8 


1 

4 

5 

18 

11 


1 






2 
24 
49 
183 
66 












3 


3 






Red-winged blackbird (Agclaiusphaniceus) 


16 
1 


1 


1 


'2 
28 
12 


2 






32 


Western meadow lark (Sturnella neglecta) 










18 


20 
2 


1 


1 


101 
50 
149 


30 
11 

40 


64 
24 
133 




































R. ust v blackbird ( Euphaqus carolinus) 

Brewer blackbird ( Euphagus cyanocephalus) . . . 


6 

139 
36 

32 
29 

68 


1 

24 

5 

2 

1 

8 


1 

40 
5 

2 
1 

15 








10 
5 
3 

2 
11 

18 






1 
19 












2 


2 






3 

6 








Great-tailed grackle ( Megaquiscalus major 


1 


1 




















Savanna sparrow (Passerculus sandwichensis, 


2 
13 
4 












1 


1 








54 


1 


1 




White-throated sparrow (Zonotrichia albico11in). 


53 

25 
27 
8 
10 
42 


1 
2 
1 
1 
1 


1 
2 
2 
2 
1 






9 


1 


1 






5 








































9 
6 








1 

7 






















39 
64 
109 
26 
5 
35 
14 
25 
19 
25 


3 
2 

18 
3 
1 

34 
5 

11 


4 

2 

19 

3 

1 

638 

52 

68 


















































1 

15 

1 




















1 


1 










1 






















16 
























Loggerhead shrike (Lanius ludovicianus) 


46 


1 


4 


4 






12 


2 


S 






1 


1 




Myrtle warbler (Dendroica coronata) 

Maryland yellowthroat (Gcothlypis trichas) 


17 
2 


1 

1 


2 
1 


3 
1 
















1 
5 
















1 


1 








American pipit (Anthus pcnsilvanicus) 


73 
43 

9 
37 
11 

1 
14 


34 
2 


120 
2 








8 
5 
29 
7 
2 


3 


4 


13 

7 
31 






85 


5 


5 










1 
5 


1 




6 
1 

1 
5 


9 
3 
2 

7 


1 


2 


1 
3 






6 


























Tufted titmouse (Bxolophus bicolor) 

Black-erestod t itmouse (Bxolophus atricristatus) 
Carolina chickadee {Pcnthcstes carolinensis) 


23 






















1 
1 






2 
1 


1 


1 


6 


1 


1 





























It will be noticed that the largest numbers of boll weevils were 
eaten during the months of July, August, and September, and also 
that a considerable number are consumed during the hibernating 
season. The most important birds are those that capture the boll 
weevil during the winter. According to this table these are the 
three species of blackbirds, two meadowlarks, six species of native 
sparrows, the pipit, the three species of wrens, and the two species 
of titmice. It will be noted that only one of the 108 quail stomachs 
examined showed remains of the boll weevil. 



THE MEXICAN COTTON-BOLL WEEVIL. 



147 



REPRESSION. 



EFFECT OF BURIAL OF SQUARES AND WEEVILS. 

The effect of the burial of squares and weevils is of considerable 
importance for the reason that sonic degree of burial can be practiced 
in the ordinary processes of cultivation. If it were to be found 
that the weevils could be killed by a depth of burial which could be 
accomplished without interference with the root system of the 
plants this process would be of vast importance. 

At Tallulah, La., in 1910, Mr. G. D. Smith conducted an exten- 
sive series of burial experiments. The infested squares were placed 
in screened cages in the field. In each of these cages 2,000 infested 
squares were placed on October 10. A careful estimate showed 
that there were 250 live weevil stages for each 2,000 scjuares. In 
the first of the cages the infested squares were placed upon a sheet 
of wire screen 2 feet above the ground. These squares were kept 
constantly moist. In the second cage the squares were placed on 
the surface of the ground. Xo artificial moisture was supplied. 
In the third cage the squares were on the surface of the ground but 
were kept moist constantly. In the fourth cage the squares were 
buried to a depth of 2 inches and the ground was kept moist. In 
the fifth cage the squares were buried 4 inches and the ground was 
kept dry. The artificial moisture was applied three times each day 
during the course of the experiment. The ''dry" cages were cov- 
ered with canvas so that rains could not reach the squares. The 
soil in the locality was the typical "buckshot" of the Mississippi 
Delta. Immediately before the institution of the experiments 
several rains had made the soil moist. Observations on emergence 
were made from October 10 until November 15. 

Table LXVII summarizes the results of these experiments. 

Table LXVII. — Summary of experiments in (he burial of squares infested by the boll 
weevil at Tallulah, Ln.. October and November, 1'JIO. 



Cage 1 . . . 
Cage 2... 

Cage:;... 
('ago 4... 

Cam' ■">.. 

Cage 6.. 
Cage 7.. 



Conditions. 



2 feet above surface, moist 

On surface, dry 

On surface, moist 

Buried 2 inches, dry 

Buried 2 inches, moist 

Buried 4 inches, dry 

Buried 4 inches, moist 



Emergence 

1 weevils). 


Emergence. 


119 
157 

147 
62 

6 

18 



Per cent. 

47.6 
62.8 


58.8 


•_'4. 8 


.2 


.7 


.0 





It will be noticed that the greatest emergence was from the two 
cages in which the squares were placed upon the surface of the ground. 
At 2 and 4 inches beneath the surface the emergence was very small. 
When kept dry beneath 2 inches of the soil 24 per cent of the possible 
emergence occurred, but at this depth when moisture was provided 
less than 1 per cent emerged. At a depth of 4 inches 0.7 per cent 
emerged in the dry cage, but none from the same depth where mois- 
ture was provided. It may be concluded from these experiments 
that burial beneath 2 or more inches of dry soil of the "buckshol " 
variety will prevent the emergence of a large portion of the weevils. 
If the soil is kept moist with burial at 2 inches or more below the 
surface the emergence is practically negligible. This is shown most 
clearly by comparing cages 4 and 5 in the table. 



148 THE MEXICAN COTTON-BOLL WEEVIL. 

LABORATORY EXPERIMENTS IN BURIAL. 

In an experiment performed at Victoria, Tex., in 1904, 1,000 
infested squares were buried under from 2 to 5 inches of well-pul- 
verized earth. 1 Seventy-five weevils emerged. Twenty-seven wee- 
vils were found which had been unable to reach the surface. Their 
location varied from the bottom of the receptacle to just beneath 
the surface. The weighted average of the distances covered by the 
weevils which failed to reach the surface was 2 inches. 

In another series of experiments at Victoria, Tex., 74 squares were 
placed under wet soil. It was found that 16 per cent of the weevil 
stages were killed. Of the weevils which became adult 30 per cent 
emerged from the squares, but only 23 per cent reached the surface 
or escaped from an average depth of 1 inch. In these experiments, 
considering all the weevil stages present, 35 per cent died without 
escaping from the soil. 

In 1904 Prof. E. D. Sanderson performed a number of burial 
experiments at College Station, Tex. At from 0.5 inch to 1.5 inches 
below the surface 26.7 per cent of the weevils emerged; at from 2 
to 4 inches 4.7 per cent reached the surface. 

It will be noted that these laboratory experiments substantiate the 
conclusion drawn from the field experiments described previously 
regarding the greatly increased mortality brought about by deep 
burial and by moisture. 

BURIAL OF ADULT WEEVILS AT TIME OF HIBERNATION. 

On or after November 23, 1903, at Victoria, Tex., 1,000 adult 
weevils were buried under from 2 to 6 inches of soil which contained 
from 9 to 19 per cent of water. Only five of these weevils succeeded 
in reaching the surface. Four of those which escaped and one which 
was still buried in the earth were found alive when examination was 
made on March 16, 1904. All the remaining weevils appear to have 
died where they were buried. 

CONCLUSIONS FROM BURIAL EXPERIMENTS. 

The field and laboratory experiments to which references have been 
made indicate that the boll weevil has comparatively little ability to 
emerge from moist soil, while dry, partially pulverized soil offers 
small obstacles to their emergence. The experiments also show that 
burial, even under moist conditions, would have to be as deep as 2 
inches to bring about very decided results. The practical question 
therefore is whether in cotton fields the soil can be turned over to 
a depth of 2 inches during the growing season without injury to the 
crop. As is well known, one of the most important cultural methods 
in producing cotton is shallow cultivation. The reason for this is 
that the plant sends many lateral roots almost at right angles from 
the rows and at a very short distance beneath the surface. Many 
of these lateral roots lie only 2 or 3 inches beneath the ground. If 
they were disturbed, the plants would react by shedding the squares. 

Undoubtedly the loss of fruit from this cause woidd more than 
offset any possible advantage accruing from the destruction of the 

1 Much more thoroughly pulverized than would be the case in the field. 



Bui. 114, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XIX. 




Fig. a. — Cotton before treatment with Paris green. (Original.) 




Fig. b. — Cotton one week after treatment with Pari* green. (( triginal.) 

Effect of Paris Green on Cotton. 



REPRESSION. 149 

weevils by burial. It is thus clear that as a means of controlling 
the weevil during the growing season the burial of squares is imprac- 
ticable. There is a time, however, when the burial of the squares 
can be carried on to excellent advantage. This is in the fall when 
the maximum infestation has been reached. Under these conditions 
it makes no difference to the planter whether the lateral roots of the 
cotton plant are cut or not. The fruit already set on the plants will 
develop in either case, and any additional fruit inevitably will be 
destroyed by the insects. Consequently the planter may destroy 
many of the weevils which would mature in a short time to feed, 
multiply, and enter hibernation, to emerge and damage the crop of 
the succeeding season. In this way deep fall cultivation is a pre- 
liminary step that should be practiced in connection with the destruc- 
tion of the plants. It should precede that process and should by 
no means be depended upon to take the place of it. After the plants 
have been uprooted and brought into windrows previous to burning 
it is advisable to plow the fields to a depth of at least 2 inches. This 
will result in the burial of many squares which were on the ground 
at the time of the uprooting or which fell during the process. The 
experiments show that the effectiveness of burial either before or 
after the uprooting of the plants will increase greatly if rains occur 
after the work is done. Likewise it is evident that the destruction 
of the weevils will be much greater in heavy soils than in lighter 
formations. In the Mississippi-Yazoo Delta the general nature of 
the soils is more or less heavy. This and the heavy precipitation in 
that region indicate a means of destroying the weevil that is especially 
important on account of the scarcity of direct means available. 

INSECTICIDES. 1 

From the very beginning of the work on the boll weevil much atten- 
tion has boon given to testing the more promising insecticides. As 
one result of the offer of a $50,000 prize by the State of Texas for an 
efficient remedy for the boll weevil, large numbers of supposed reme- 
dies have been proposed. Doubtless the inventors have been per- 
fectly sincere in their faith in the efficiency of these compounds. As 
was fully anticipated by the entomologists when the reward was 
offered, the commission charged with awarding the money was 
deluged with applications therefor, the claims in a large majority of 
cases being based upon some concoction supposed by the inventor to 
possess marvelous insecticidal properties. In comparatively few 
cases had the new product been tested in any way. Often samples 
were sent with the request that tests be made. Many of these inven- 
tions found their way to the various laboratories of this investigation, 
where it has been the uniform policy to give every thing of this kind 
a fair test and report the results to the originator. Tests were made 
in the field upon weevils confined by cages. This work has required a 
great deal of time, and the results have failed to indicate a single new 
compound having real value. Many of the substances tried had 
absolutely no effect on either plant or insect life, while others were 
equally fatal to both wherever they came in contact with them. The 
primary difficulty with all such insecticides lies in the fact that, 

1 The first two paragraphs under this heading have been modified from Bull. 51, Bureau of Ento- 
mology, p. 156. 



150 THE MEXICAN COTTON-BOLL WEEVIL. 

owing to the peculiar habits and life history of the weevil, the poison 
can not be so applied as to reach the immature stages at all, and it can 
not reach the adults so as to cause sufficient mortality to result in any 
considerable benefit to the crop. Much work has been done in thor- 
oughly testing the effect of Paris green. The most important results 
of this work have already been published in Farmers' Bulletin No. 211 
of the Department of Agriculture. They will be described briefly on a 
subsequent page. 

Among 40 other compounds tested, none proved worthy of even 
passing consideration for field use. As a fumigant for seed, among 
the eight gases or vapors tested, carbon bisulphid was found to 
possess considerable value when applied in the special manner 
described on pages 162, 163. 

POWDERED ARSENATE OF LEAD. 

In 1909 Messrs. Wilmon Newell and G. D. Smith, then of the 
Louisiana Crop Pest Commission, published the results of certain 
work with powdered arsenate of lead as a remedy against the boll 
weevil. This work was done in central Louisiana during the season 
of 1909. The principal experiments were located on three different 
plantations on plats provided for the purpose. From 1 to 10 appli- 
cations were made, consisting of a total amount of poison of from 1 to 
51 pounds per acre. The treated cotton yielded an average of 71 per 
cent more than similar cotton which was not treated. In all except 
one of the plats there was a net profit from the use of the poison (that 
is, after deducting the cost of the poison and of the labor from the 
value of the increased yield) of from 27 cents to $23.54 per acre. In 
the one exception there was a loss of $7.07 per acre. 

These striking results led to extensive work on powdered arsenate 
of lead by the Bureau of Entomology. The services of Mr. G. D. 
Smith, who was directly connected with the Louisiana work to which 
reference has been made, were obtained. The bureau instituted 
numerous experiments in Louisiana, including several which dupli- 
cated the previous work in that State. Tins investigation has now 
extended through two seasons in Louisiana, and considerable work 
has also been done at Victoria, Tex., by Mr. J. D. Mitchell. 

In the experiments of 1910, 32 plats were utilized on plantations 
at Livonia, Shaw, and St. Joseph, La., and Victoria, Tex. In the 
work in Louisiana there was a profit from the use of the poison on 20 
of the plats and a loss on the 12 remaining plats. The average loss 
on the plats which failed to show a profit was $6.99 per acre. The 
average profit on the remaining plats was $5.83 per acre. Twenty- 
two of the 32 plats showed an increased yield of from 35 pounds to 403 
pounds of seed cotton per acre. A striking result was the fact that 
invariably the plats upon which small amounts of the poison were 
applied showed profits. The work at Victoria, Tex., in 1010, con- 
sisted of four experiments. In only one of these experiments was a 
gain in yield obtained, and this amounted to only 59 pounds of seed 
cotton per acre. In all of the experiments at this place there was a 
loss from the application of the poison of from $1 .55 to $6.52 per acre. 

In 1911 the work on powdered arsenate of lead was continued. In 
some respects the results were contradictory of those obtained pre- 
viously, but there was agreement in that profits were obtained on all 



REPRESSION. 151 

plats whore small applications were made. On account of the 
apparent contradictions and the variations due to the seasons it is 
considered necessary to continue the work another season before 
definite conclusions as to. the practical value of arsenate of lead can 
be drawn. 

MACHINES. 
FIELD MACHINERY. 

Many attempts have been made to perfect machines that will 
assist in the warfare against the weevil. The only one of direct 
value that has been perfected is the chain cultivator (PI. XX, b; 
PI. XXI) invented by Dr. W. E. Hinds, formerly of the Bureau of 
Entomology, and patented by the Department of Agriculture for the 
benefit of the people of the United States. Its construction is based 
upon the discovery that the weevils in the infested squares that fall 
in such position as to be reached by the sun soon die. In a cotton 
field many of the infested squares fall within the shade of the plants, 
and are thus protected. The chain cultivator is designed to drag 
the fallen squares to the middles of the rows and leave them exposed 
to the sun. This it has been found to accomplish in a satisfactory 
manner. In fact, in tests the use of the machine has been found 
to result in a decided gain in production. 

Although the chain cultivator was designed primarily for bringing 
the squares to the middles, it was found in field practice to have a 
most important cultural effect. The chains (so-called "log chains") 
are heavy enough to establish a perfect dust mulch and to destroy 
small weeds that may be starting. In fact, it is believed that this 
cultural effect would more than justify the use of the machine, 
regardless of the weevil. In view of the effect against the insect and 
the important cultural effect, it is believed that this implement or one 
similar to it should be used by every farmer in the weevil territory. 

The chain cultivator is now regularly manufactured by one of the 
large dealers in farm implements, but a satisfactory machine can be 
made by any blacksmith. Full directions are to be found in Farmers' 
Bulletin 344, a copy of which may be obtained upon application 
to the Secretary of Agriculture. 

Some forms of cultivators now in use allow the attachment of 
boards which drag on the ground and carry the infested squares to the 
middles. In fact, the principle of the chain cultivator can be incorpo- 
rated in many implements now in use. It is strongly recommended 
that this be done for weevil control as well as for obtaining a dust 
mulch. 

1 Many machines have been designed to jar the weevils and 
infested squares from the plant and to collect them, to pick the fallen 
squares from the ground, to kill by fumigation, and to burn all 
infested material on the ground. The Bureau of Entomology has 
carefully investigated the merits of representatives of all of these 
classes, beginning in 1895 with a square-collecting machine that had 
attracted considerable local attention in Bee County, Tex. Up to 
the present time none of these devices has been found to be practical 
or to offer any definite hope of being eventually successful. At one 

1 The following tlu-ee paragraphs are modified from Bull. 51, Bureau of Entomology, p. 157. 



152 THE MEXICAN COTTON-BOLL WEEVIL. 

time there seemed some hope that a machine designed to pick the 
squares from the ground by suction might be perfected. The 
experiments, however, have indicated probably insurmountable 
difficulties; and a large implement concern, after having experimented 
with the matter fully, has come to the conclusion that mechanical 
difficulties will always prevent the perfection of such a machine. 

The ultimate test of all methods or devices for controlling the 
weevil is to prove through a series of seasons, and under a large 
variety of conditions, that by their use there is produced an increase 
in the crop treated or protected of sufficient value to more than 
repay the expenses of the treatment or protection. As a general 
rule, where machines have been used or poisons applied, planters 
have provided no check upon the results obtained and have kept no 
close records as to the expense involved and net gain or loss resulting 
from the treatment. The result of such applications is, therefore, 
merely a general impression of gain or loss which may not agree 
at all with the facts. 

In this connection it must be stated that all machines which 
assist in more satisfactory methods of preparation of the land and 
cultivation of the crop are of indirect advantage. This is especially 
the case with devices which increase the amount of work that a single 
hand or team of mules may do. In fact, the boll weevil has been the 
cause of much commendable improvement of agricultural machinery 
throughout the infested territory. 

GINNING MACHINEKY. 1 

The more important results of studies upon this class of machinery 
were presented in Farmers' Bulletin No. 209 of the Department of 
Agriculture. Modern cleaner feeders were found to be quite efficient 
in separating the weevils from the seed cotton, as they removed fully 
70 per cent of the weevils passing into them. Of the weevils removed, 
over 80 per cent were still alive when taken from the trash. This 
fact shows the necessity for the use of some additional device which 
will crush or otherwise destroy all weevils taken from the cotton by 
the cleaner feeder. (See PI. X, a.) 

For the weevils escaping the action of the cleaner feeder and passing 
into the ginning breast with the roll there are two avenues of escape — 
one with the seed, the other with the motes. In these two ways it 
appears that over 85 per cent of the weevils passing into the gin 
breast escape alive, while the remainder are killed by the saws. 
From these facts it is evident that some way should be provided for 
properly caring for the motes so as to confine the weevils which are 
thrown out among them and secure their destruction with those 
removed by the cleaner feeder. Some method should also be 
devised for separating from the seed the weevils that pass the saws 
before they reach the seed house or the farmers' seed bins. 

When we consider the important effect that gins have been found 
to possess in spreading the weevil, especially near the border line of 
infestation, it appears exceedingly desirable that improvements in gin 
machinery should be made in the following particulars: 

First. The area and distance through which the action of the picker 
roll in the cleaner feeder is continued should be considerably increased, 

1 This section is mc-'lifted from Bull. 51, Bureau of Entomology, pp. 158, 159. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XX. 






u 



SMP 



A ^^HF"^^^' 




-* 









tftkb 




r*fe. 



7'V;/. a.— I 



arly fall destruction of stalks, the fundamental method for controlling the boll weevil. 
Windrowing stalks for burning. (Original. ) 




Fig. b. — Chain cultivator passing through cotton rows. (Original.) 
Cultural Control of the Boll Weevil. 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XXI. 





go 



REPRESSION. 153 

compression rollers or some other device being employed to destroy 
the weevils separated by the cleaner. 

Second. Some method should be devised for keeping under control 
the weevils escaping alive with the motes, as under present conditions 
they have free range through the ginnery. 

Third. Possibly the most important of the devices needed is an 
apparatus which may be applied near the gin (possibly as the seeds 
leave the gin breast and drop into the seed chute) by which the 
weevils may be separated from the seed and brought under control, 
so that they may be destroyed. 

With these improvements the oil mills would almost cease to be a 
factor in the dissemination of weevils, and the movement of seed, 
either for planting, stock feeding, or fertilizer, would practically cease 
to be what it is at present, a factor in the spread of the weevil. 

FUTILE METHODS WHICH HAVE BEEN SUGGESTED. 1 

MINERAL PAINT AND COTTONSEED OIL. 

The very serious nature of the boll-weevil problem is constantly 
illustrated by the manner in which various useless devices and nos- 
trums are brought to public attention. At one time it was widely 
alleged that mineral paint would act as a specific against the weevil. 
An equally fallacious theory that also received considerable popular 
attention was to the effect that cottonseed meal exerted a powerful 
attraction for the pest. 

SPRAYING. 

Probably the most important useless recommendation has been 
that of spraying. It was supposed for some time by certain parties 
that it might be possible to poison weevils economically by attracting 
them to some sweetened preparation. The experiments conducted 
to determine the attraction of various sweetened substances demon- 
strate the fallacy of the theory. Even if these substances exerted as 
much attraction as was supposed, there would be insurmountable 
difficulties in the application of the method in the field. It is true 
that it is possible to destroy a certain number of weevils in regions 
where stubble cotton occurs by heavily spraying the earliest plants, 
but this method is of immeasurably less importance than the simple 
practice of cultural methods. 

SULPHUR. 

The old idea, the fallacy of which has been explained repeatedly by 
economic entomologists for the past 50 years, namely, that sulphur 
can be forced into the system of the plants to make them immune to 
insect attack, sometimes crops out with reference to the boll weevil. 
It is scarcely necessary to call attention to the fallacy of attempting 
to destroy the boll weevil by soaking the seed in chemicals with the 
hope of making the plants that are to grow from them distasteful or 
poisonous to the insect. Any money expended by the farmer in 
following this absurd practice is entirely wasted. 

1 This section is greatly modified from Bull. 51, Bureau of Entomology, pp. 159, 160. 



154 THE MEXICAN COTTON-BOLL WEEVIL. 

PARIS GREEN. 

One of the most important fallacies regarding a remedy for the boll 
weevil was that which received great attention during the season of 
1904, namely, that Paris green is a specific for the pest. The urgent 
demand for a specific was evidenced by the very extensive use of this 
substance. A portion of the great attention that it received pub- 
licly was due to the fact that early in the season a certain number of 
weevils may be killed by it. Applications made by spraying are even 
less effective than dusting with the dry Paris green. As was pointed 
out in Farmers' Bulletin No. 211, which deals with exhaustive field 
and laboratory experiments with Paris green, the number so de- 
stroyed in the spring really means nothing whatever to the crop 
later in the season when the plants have put on squares and the 
poison is no longer effective. As a matter of fact, the uselessness of 
Paris green was quickly discovered by planters. Since 1904 prac- 
tically none has been used in the warfare against the pest. (See 
PI. XIX.) 

TRAPPING AT LIGHT. 

There is still, in many quarters in Texas and Louisiana, a supposi- 
tion that it is possible to attract the boll weevil to lights. A number 
of machines have been constructed based upon this idea. Whether 
or not the boll weevil can be attracted to lights was one of the first 
matters that was investigated by entomologists. During September, 
1897, Mr. J. D. Mitchell, of Victoria, Tex., a naturalist and cotton 
planter, set out trap lanterns in a cotton field in Victoria for one 
night, and sent the insects captured to this bureau for examination. 
In all, 24,492 specimens were taken, representing approximately 328 
species. Divided according to habit, whether injurious or beneficial, 
the result was: Injurious species, 13,113 specimens; beneficial spe- 
cies, 8,262 specimens; of a negative character, 3,117. The interest- 
ing point in connection with this experiment was the fact that not a 
single specimen of the boll weevil was found, although the lights were 
placed in the midst of fields where the insects were very abundant. 
Since that time other investigators have looked into this matter fully. 
Lights have been kept burning in cotton fields night after night for 
several weeks. In no case has a single specimen of the boll weevil 
been discovered, although thousands of species of insects have been 
captured. 

The popular misapprehension about the possibility of capturing 
the boll weevil at lights is due to the fact that somewhat similar 
insects, Balaninus victoriensis, and other acorn weevils, differ from 
the boll weevil in that lights exert a strong attraction for them. Dur- 
ing occasional seasons the acorn weevils are exceedingly common in 
Texas, and great numbers of them fly to the electric lights. 

OTHER PROPOSED REMEDIES. 

Hundreds of proposed remedies, in addition to those which have 
been mentioned, have been carefully investigated. The claims of 
their advocates in practically all cases are based upon faulty obser- 
vations or careless experiments. The strong tendency of the weevil 
to die in confinement, which has been referred to, has caused many 



REPRESSION. 155 

honest persons to suppose that the substances tney are applying have 
killed it. Moreover, an insuperable difficulty that these special 
preparations have encountered is the impracticability of the appli- 
cation in the field. Hundreds of known substances will kill the 
weevil when brought into contact with it. The difficulty is to apply 
them in an economical way in the field. The claims made at different 
times of the repellent power of tobacco, castor-bean plants, and 
pepper plants against the boll weevil have no foundation whatever. 
In fact, none of these plants has the least effect in keeping weevils 
away from cotton. 

REQUIREMENTS OF A SATISFACTORY METHOD OF BOLL-WEEVIL 

CONTROL. 1 

The difficulties in the way of controlling the boll weevil lie both in 
its habits and manner of work and also in the peculiar industrial 
conditions involved in the production of the staple in the Southern 
States. The facts that in all stages, except the imago, the weevil lives 
within the fruit of the plant, well protected from any poisons that 
might be applied, and in that stage takes food normally only by insert- 
ing its snout within the substance of the plant; that it frequently 
requires only 12 days for development from egg to adult, and the 
progeny of a single pair in a season may exceed 3,000,000 individuals; 
that it adapts itself to climatic conditions to the extent that the egg 
stage alone in November may occupy as much time as all the imma- 
ture stages together in July or August, are factors that combine to 
make it one of the most difficult insects to control. It is, conse- 
quently, natural that all the investigations of the Bureau of Ento- 
mology have pointed toward the prime importance of methods of 
control which involve no outlay for materials and very little for labor. 
Methods which involve some direct financial outlay for material or 
machinery are not in accord with labor conditions surrounding cotton 
production in the United States. Moreover, the indirect methods 
advocated are in keeping with the general tendency of cotton culture* 
that is, to procure an early crop, and at the same time have the great* 
advantage of avoiding damage by a large number of other destruc- 
tive insects, especially the bollworm. Nevertheless it must not be 
understood that attention has not been paid to the investigation of 
means looking toward the direct extermination of the pest. Much 
work has been done, but the results have all been negative. 

BASIS FOR MEANS OF REPRESSION. 

In spite of the many difficulties involved in the control of the boll 
weevil certain generally satisfactory means of repression are at hand. 
They consist of both direct and indirect means. Those of an indi- 
rect nature are designed to increase the advantage gained by the 
direct measures and to increase the effectiveness of the several natu- 
ral factors which serve to reduce the number of weevils. Thus, the 
control measures constitute a combination of expedients, the parts 
of which interact in many ways. Naturally, the best results are 
obtained when the planter can put into practice all of the essential 
parts of the combination. 

1 This section is greatly modified from Bull. 51, Bureau of Entomology, pp. 160, 161. 



15G THE MEXICAN COTTON-BOLL WEEVIL. 

It is obvious that any method of controlling the boll weevil must 
depend upon full knowledge regarding its life history and the natural 
forces which tend to prevent' its multiplication. Certain practices 
which upon superficial observation might be considered important 
in the control of the insect upon investigation may be found to be 
of no avail whatever. In fact, in some cases what appear to be 
feasible means of control are worse than useless, because they tend 
to nullify the effects of natural forces which act against the weevil. 
This is notably the case with the practice of attaching a bar to a 
cultivator to jar the infested squares from the plants. As will be 
explained later, this practice is of advantage only under very restricted 
conditions. Throughout the greater part of the infested territory it 
is an assistance rather than a hindrance to the boll weevil. 

There are seven features of the life history of the weevil that are 
of cardinal importance in control. These are indicated below. 

1. The weevil has no food plant but cotton. 

2. The mortality of the weevil during the winter is very high. 

3. The emergence from hibernating quarters during the spring is 
slow and prolonged until well into the summer. 

4. Early in the season, on account of comparatively low tempera- 
tures, the development of the weevil is much slower than during the 
summer months. 

5. The drying of the infested squares, as the result of heat, soon 
destroys the immature stages of the weevil contained therein. 

6. The weevil is attacked by many different species of insect ene- 
mies, the effectiveness of which is increased by certain practices. 

7. The weevil has but little ability to emerge when buried under 
wet soil. 

Exactly how each of these features of the life history of the weevil 
affects plans for practical control will be explained in the following 
paragraphs. 

In the case of many of the important injurious insects the problem 
of control is greatly complicated by the fact that the pests can sub- 
sist upon more than one food plant. In some cases a single species 
attacks several cultivated crops. In other cases the pests can sub- 
sist upon native plants practically as well as upon the cultivated 
species. All these difficulties are absent in the case of the boll-weevil 
problem. As has been shown in the preceding pages, the insect is 
absolutely restricted to the cotton plant for food and for opportu- 
nities for breeding. The problem is therefore much more simple than 
it would be if the weevil could subsist upon any other plant in the 
absence of cotton. This peculiarity of the weevil was the basis of 
the recommendation made in 1894 that the pest be exterminated 
absolutely in the United States by the abandonment of cotton. At 
that time only a few counties in Texas were affected. The procedure 
would have involved small expense. Even now the weevil could be 
exterminated in a single season by preventing the planting of cotton 
and the growth of volunteer plants. This proposal has been made 
at various times, notably at the national boll-weevil convention held 
in Shreveport, La., in 1906. 

Various difficulties, however, appear to render the plan entirely 
impracticable. In the first place, there would be strong opposition 
in large regions in Texas where the planters have learned to combat 



REPRESSION. 157 

the weevil successfully. This opposition would undoubtedly be 
sufficiently strong to prevent cooperation in a large territory. More- 
over, the expense would be enormous. A large army of inspectors 
would be required. The work would not end with the prevention 
of planting cotton, but would necessarily extend to the destruction 
of volunteer plants winch would be found along roads, railroads, 
about gins and oil mills, and on plantations throughout the infested 
region. The loss to mills, railroads, merchants, banks, and others 
dependent upon the cotton trade would complicate matters further. 
Unless a plan of reimbursement were followed there would be stren- 
uous opposition from these quarters, and any scheme of payment for 
damages would increase the cost still further. From a theoretical 
standpoint all the expenses involved would be justified. The saving 
in a few years would more than offset the cost. Nevertheless, the 
practical difficulties undoubtedly will always prevent the execution 
of the plan. All interests now seem to favor the necessary adjust- 
ment of conditions to the boll weevil rather than total eradication — 
once practicable but now little more than visionary. 

Under the discussion of the hibernation of the weevil it was shown 
that during the several years in which careful experiments have been 
performed the average rate of survival was 7.6 per cent. It is note- 
worthy that frequently the survival is much smaller. In the ex- 
periments to which reference has been made it ranged from 0.5 per 
cent to 20 per cent. The most important means of controlling the 
boll weevil that are available are designed to increase the tremendous 
mortality caused by natural conditions during the winter. The 
destruction of any certain number of weevils during the winter is 
much more important than the destruction of much larger numbers at 
any other season. The best means at the command of the farmer for 
increasing the winter mortality is through the uprooting and burning 
or burial of the stalks at an early date in the fall. (See PI. XX, a.) 
Numerous experiments have shown the lessened mortality due to 
depriving the weevils of their food at early dates in the autumn. In 
fact, the experiments showed a practically uniform increase in the 
number of weevils surviving as the dates of the destruction of the 
plants became later. For instance, in all of the experiments per- 
formed in Texas it was found that destruction in September re- 
sulted in a survival of only 0.2 per cent; destruction two weeks later 
showed a survival of 2.3 per cent; destruction during the last half of 
October, 5.6 per cent; and during the first half of November, 15.4 
per cent. The results of the Louisiana experiments were similar. 
Destruction in September showed a survival of 0.3 per cent; destruc- 
tion in the first half of October, 2 per cent; in the last half of October, 
8 per cent. 

In addition to the experiments in which the weevils have been 
placed in cages at different times in the fall, the Bureau of Ento- 
mology has conducted considerable field work to show the benefits 
of fall destruction. The most striking experiment was performed 
at Calhoun County, Tex., in 1906. In this experiment an isolated 
area of over 400 acres of cotton was utilized. There was no other 
cotton within a distance of 15 miles. By contracts entered into by 
the department, the farmers uprooted and burned all of the stalks 
during the first 10 days in October, and pro vision was made to prevent 



158 THE MEXICAN COTTON-BOLL WEEVIL. 

the growing of sprout cotton. As a check against this area, cotton 
lands about 30 miles away were used. Here the stalks were not de- 
stroyed in the fall, and the interpretation of the results of the experi- 
ment was based upon a comparison of the number of weevils present 
during the following season in the two localities. In May following 
the destruction of the plants careful search revealed only one weevil 
in the experimental area. In the check, however, the weevils were 
so numerous at this time that practically all of the squares had been 
destroyed. Examinations made later showed similar advantage in 
regard to freedom from the boll weevil of the area where the stalks 
were destroyed in October. The last examination was made on 
August 20. At this time there were 10 sound bolls to the plant on 
the experimental area and only 3 to the plant in the check area. 
The difference in yield between the two areas was about 600 pounds 
of seed cotton per acre. The work, therefore, resulted in an advan- 
tage amounting to about $18 per acre. 

Newell and Dougherty 1 have described a very satisfactory device 
for cutting the cotton stalks in the fall. It consists of a triangular 
wooden framework, designed to pass between the rows and cut two 
at the same time. In the process of cutting, the machine windrows 
the stalks from two rows into the middle between the rows. The 
runners are provided with knives made of sharpened metal. Old 
saws have been found well adapted to the purpose. It is important 
to provide a metal runner at the rear end of the machine to prevent 
sliding. This runner is designed to run an inch or more beneath 
the surface of the ground. The device can be made by any black- 
smith at a cost of about $4. It will cut and windrow from 10 to 15 
acres of stalks in a day. 

There is a disadvantage in cutting the stalks at or near the surface 
of the ground : If warm weather follows, many of the roots will give 
rise to sprouts that will furnish the weevils food. On this account 
the process is less effective than uprooting the plants. Wherever 
the stalk cutter is used, it should be followed by plows to remove the 
roots from the ground. 

There is another important means by which the winter mortality 
of the weevil may be increased. Tins is by removing the hibernating 
quarters or destroying them after the weevil has gone into hibernation. 
Many of the insects are to be found in the winter in trash and debris 
found in and about cotton fields. The more shelter there is provided 
in the form of weeds growing about the fields, the more favorable 
the conditions will be for the insect. By the burning of such hiber- 
nating quarters as are found in the cotton fields and in their immediate 
vicinity a farmer can cut off a very large proportion of the weevils 
that would otherwise emerge to damage the crop. 

The prolonged period of emergence from hibernation gives the 
planter another important advantage over the weevil. It has been 
shown on preceding pages that the period of emergence from hiber- 
nation extends, in normal seasons, to practically the 1st of July. 
In fact, except in one of the experiments that was performed, the 
last weevils aid not appear until after the 20th of June. In the one 
exception the last weevils appeared on the 6th of June. In Texas 
it was found that 75 per cent of the emerging weevils appeared after 

1 Cir. 30, Louisiana Crop Pest Commission. 



EEPEESSION. 159 

April 8 and in Louisiana 64 per cent. In Texas, after May 1, in all 
the experiments, from 4 to 18 per cent of the surviving weevils 
appeared. In Louisiana, after May 1 , from 30 to 40 per cent emerged. 
It is obvious that the fact that many weevils do not appear until 
long after cotton can be planted and brought to a fruiting stage is a 
very great advantage to the planter. A portion of a crop at least 
can be set before the weevils have become active. Usually it is 

Eossible to plant a crop sufficiently early to have it set some fruit 
efore much more than 50 per cent of the surviving weevils have 
emerged. 

Attention was directed to the fact that the development of the 
weevil is much slower in the early portion of the season than later. 
For instance, at Vicksburg, .Miss., the average period of development 
in April is 30 days and in May 19 days. In June the period is short- 
ened to 15 days. Consequently the planter has an opportunity to 
force the development of fruit on the plants when the weevils are 
being held in check by the temperatures of the spring months. The 
ability of the cotton plant to grow T during April and May is much 
greater than that of the weevils. This gives a margin of which the 
planter can take advantage 1 . 

In the section dealing with natural control it was shown that 
climatic checks are the most important that the boll weevil experi- 
ences. The principal manner in which climatic factors affect the 
weevil is through the drying of the fruit. Naturally, the more heat 
and light there is to reach the fallen squares, the greater will be the 
effectiveness of the most important natural means of control. This 
is the basis for the recommendation that the plants should be given 
considerable space, not only between the rows, but in the drill. Of 
course, it would be possible to place the plants entirely too far apart, 
and thus reduce the yield. There is a happy medium, however, at 
which planters must arrive from experience on their individual 
places. At the same time, varieties should be cultivated which have 
a minimum tendency toward the formation of leafage. 

The work of the insect enemies of the boll weevil is increasing from 
year to year. This work should be encouraged in so far as possible. 
It happens that several of the recommendations made for other rea- 
sons will result in facilitating the work of the enemies of the weevil. 
This is the case with early planting, wide spacing, and the use of 
varieties with sparse rather than dense leafage. Even fall destruc- 
tion is not a disadvantage, because it forces the parasites at the 
active season to native hosts that carry them through the winter. 
Wherever possible, varieties should be planted which retain a large 
proportion of the infested squares, because the hanging squares are 
more favorable for parasite attack than those which fall. 

"Whenever the squares are picked by hand they should not be burned 
or buried, but placed in screened cages. In this way the weevils will 
be destroyed while the parasites may escape. 

Numerous experiments have shown that a large proportion of the 
weevils buried under 2 inches of moist soil can not reach the surface. 
Unfortunately, it is not possible to plow 7 the infested squares under 2 
inches of sod during the growing season. The operation would 
result in injury to the root system and cause great shedding. Never- 
theless it is possible for the planter to follow 7 this practice after 
maximum infestation has been reached and after the plants have 



160 THE MEXICAN COTTON-BOLL WEEVIL. 

been uprooted. Therefore, every means should be taken at the time 
of maximum infestation to plow under the infested squares as deeply 
as possible. This method is of little use in dry regions, but fortunately 
is of great importance in humid regions where other means of control 
are comparatively lacking in efficiency. It is also assisted greatly 
by the occurrence of large areas of so-called stiff soils in the humid 
area. 

SUMMARY OF MEANS OF REPRESSION OF THE BOLL WEEVIL. 

In the preceding pages all effective methods of controlling the 
boll weevil have been described in a general way, and their connec- 
tion with the life history of the insect shown. Further details regard- 
ing the application of the methods have been published in Farmers' 
Bulletin 344. In the present connection it will be sufficient to sum- 
marize the subject. The following are the essential features of the 
control of the boll weevil: 

1. Prevention of the invasion of new territory by means of quarantines 
directed against farm commodities that are likely to carry the weevil. 
It is not necessary to have a quarantine applied to an extended list 
of articles. Only a few forms of cotton and of cotton by-products 
need to be considered. The most important is seed cotton. Next 
in importance are cottonseed and cottonseed hulls. There is no 
danger in cottonseed meal and scarcely any appreciable danger in 
baled cotton. 

Cottonseed can be easily rendered entirely safe by fumigation with 
carbon bisulphid, as described in this bulletin. 

2. The destruction of the weevils in the fall by uprooting and burning 
or burying the plants. This is by far the most important step in con- 
trol. (See PI. XX, a.) It is so important that unless it is followed 
all other means will avail little to the planter. 

The burning of the cotton plants is, of course, a bad agricultural 
practice. It should not be followed except in extreme emergencies. 
In all other cases the plants should be uprooted as soon as the cotton 
can be picked and cut by means of stalk choppers and immediately 
plowed beneath the surface. The ground should afterwards be har- 
rowed or dragged to make it still more difficult for the insects to 
emerge. 

In many cases it will be found inadvisable to wait for the uprooting 
of the plants until all of the cotton is picked. After only a small 
portion remains for the pickers, it is entirely feasible to uproot the 
plants by means of a turning plow and leave them in the field so that 
the cotton can be picked. This will hasten the opening of the green 
bolls and frequently result in a considerable saving to the planter. 

3. The destruction of the weevils during the winter. This is accom- 
plished by the destruction of the places in which the insects hibernate. 
Many such places are found in the cotton fields or in their immediate 
vicinity. A certain number of the weevils will of course make their 
way into the heavy woods and other situations beyond the reach of 
of the planter, but many remain where they can be reached. 

4- Obtaining an early crop. (See PI. XXII.) The importance of 
obtaining an early crop has been shown to depend upon the small 
number of weevils which hibernate successfully, their late emergence 
from hibernating quarters, and their comparatively slow development 



Bui. 1 14, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XXII. 



■fi -h ii ni iii mm*tmmm*mm*m*mmmsM*m*-- 





Fig. a. — Late-planted cotton under boll-weevil conditions, given same culture as early planting 

(Original.) 




Fig. b.— Early-planted cotton adjoining the late planting under same conditions. (Original.) 

Results of Early and Late Planting of Cotton. 



REPRESSION. 161 

during the early part of the season. The obtaining of an early crop 
is brought about by early preparation of the soil, by early planting, 
by the use of early-maturing varieties, by a system of fertilization 
which will stimulate the growth of the plants, and by continuous 
shallow cultivation during the season. 

5. Increasing the effects of climatic control. As has been shown, 
practically 50 per cent of all the weevil stages throughout the infested 
territory are destroyed by climatic influences. This means that the 
power of reproduction of the weevils is reduced by one-half. A 
planter can increase the advantage in his favor by providing a suitable 
distance between the plants and between the rows. It is also impor- 
tant to use varieties, where possible, which have a comparatively 
small leaf area. The use of the chain cultivator will be found of 
great value in connection with obtaining the full effects of climatic 
control. 

6. Encouraging the insect enemies of the weevil. This is accom- 
plished in part by procedures already recommended and further by 
the use of varieties which have a well-developed tendency to retain 
the fruit and which also have a comparatively open structure and 
small leafage. 

7. Hand picking of weevils and squares. This is a practice of little 
general importance. Although under some local conditions it may 
be highly advisable, everything depends upon the cheapness with 
which the work can be done. On crops produced by wage hands it 
is doubtful if the hand picking of the weevils or squares will ever 
result in any profit. Where the crop is produced on the share basis, 
and the acreage is sufliciently small to allow considerable work in the 
picking of the squares, the practice will undoubtedly pay. It is, 
therefore, a matter that must be taken into consideration by each 
individual planter. It can not be recommended generally, for the 
reason that under many conditions it would result in loss. 

Wherever square picking is practiced the squares should not be 
burned. They should be placed in cages, so that the parasites may 
escape and continue their work. As a matter of fact, under most 
conditions it is likely that the encouragement that can be given the 
parasites by this means is of much more importance than any direct 
checking of the weevil by the process of hand picking. Wherever 
squares are burned the planter is merely destroying the enemies of 
the weevil and consequently working against his own interest. 

8. Control at gins. — The use of modern cleaner feeders will eliminate 
practically all of the weevils from cottonseed. Such devices should 
be used at least in the case of all seed that is intended for shipment 
into any infested localities and especially along the outer border of 
the infested territory, where wagons may carry infested cottonseed 
some distance into territory that has not been reached by the weevil. 
It is important in connection with the cleaner feeders to provide 
some means for the destruction of the insects that are captured. In 
some cases where the cleaner feeders are in operation the discharge 
is allowed to accumulate in an open barrel or box. From such recep- 
tacles weevils readily make their way into the seed cotton in storage. 
It is a simple matter to provide compression rollers through which 
the discharge from the cleaner feeder is passed. If, for any reason, 
the use of compression rollers is impracticable, the trash should bo 

28873°— S. Doc. 305, 62-2 11 



162 THE MEXICAN COTTON-BOLL WEEVIL. 

fumigated at frequent intervals by means of carbon bisulphid or col- 
lected in a closed chamber and burned before the weevils have an 
opportunity to escape. (See PI. X, a.) 

9. Fumigation of seed (fig. 34). This is a means of repression that 
will be of avail only in the case of shipments of seed into uninfested 
territory. It has been found that carbon bisulphid is the most sat- 
isfactory agent to use. Great care should be taken to insure thor- 
oughness of application. 

The use of a crossbar attached to the cultivator to jar the infested 
squares from the plants has frequently been recommended. Under 
some conditions this practice should be followed, but under others it 
is worse than futile. It was shown, in the treatment of the subject 
of natural control of the weevil, that in the humid region, including 
Arkansas, Louisiana, and the eastern portion of Texas, the mortality 
in hanging squares is greater than in fallen squares. For this reason 
it is better for the squares to remain on the plants. There is another 
reason why they should be allowed to remain on the plants which 
applies especially to the moist region in which the boll weevil is now 
doing great damage. This is, that the hanging squares are much 
preferred by the boll- weevil parasites. The records have invariably 
shown a higher rate of parasitism in hanging squares than in fallen 
squares. In this way the hanging squares furnish a means for the 
breeding of parasites, thereby enabling them to establish themselves 
in the field. 

It will be noted that the means of repression of the boll weevil may 
be divided into two classes, namely, direct and indirect. 

The direct means of control are the destruction of the weevils in 
the fall by destroying the plants and burning or burying the immature 
stages, hand picking of weevils and squares under some conditions, 
the burial of the infested forms at the time of maximum infestation, 
and the burning of the hibernating weevils in their winter quarters. 

The indirect means of control are early planting, the use of early 
varieties and of fertilizers that will accelerate growth, the selection 
of fields where the soil is suitable to rapid development, frequent 
shallow cultivation, the encouragement of the parasites of the weevil 
by placing the infested squares that may be picked by hand in cages 
instead of burning them, and the use of machinery which facilitates 
the various operations in preparing the land and cultivating the crop. 
These have the effect of increasing the acreage that a hand may cul- 
tivate. In view of the fact that the boll weevil forces a reduction in 
the acreage per hand, this is a consideration of some moment. 

DESTROYING THE BOLL WEEVIL IN COTTON SEED. 

It has been shown in this bulletin that adult weevils are frequently 
to be found in cotton seed and that there is danger in the dissemina- 
tion of the pest through the shipment of the seed. A number of 
experiments have been performed to discover means of killing the 
weevils found in seed. There are great difficulties to be overcome 
on account of the density of the seed and its practical impenetra- 
bility by certain fumigants. It was shown, for instance, that hydro- 
cyanic-acid gas has practically no penetrating power whatever. 
Carbon bisulphid was found to be satisfactory, although a special 
apparatus and special manipulation of the seed are necessary to insure 



REPRESSION. 



163 



success. The method described below, from Farmers' Bulletin 209, 
is that which has been used by the bureau in cases where it has been 
necessary to free cotton seed of the weevils. 

The following plan for this work is proposed : A tight matched-board box should be 
provided having sides 4 feet high, open on top, and of other dimensions to accommodate 
12 or more 100-pound sacks of cotton seed placed upright upon the bottom. Another 
tier of sacks could be added if desired. Into each one of these sacks about 1 ounce of 
carbon bisulphid should be forced by an apparatus for volatilizing the liquid and mix- 
ing the vapor with air. The accompanying illustration (fig. 34) will give an idea of 
this apparatus. It should consist of three essential parts, as shown in the illustration. 
A is an air pump having sufficient storage capacity to enable it to maintain a steady 
discharge of air for several 
minutes without continu- 
ous pumping. The stop- 
cock at a x regulates or 
prevents the escape of air, 
as may be desired. B is 
an ordinary 2-quart bottle 
fitted at b 1 with a tight 
stopper of good length, 
having two openings, 
through which the inlet 
and outlet pipes pass. 
These pipes may be of 
glass or metal and should 
be as large as can be used. 
The inlet pipe, b 2 , reaches 
nearly to the bottom of the 
bottle and is provided at 
the lower end with a per- 
forated metal cap as large 
as will pass through the 
neck of the bottle. This 
allows the escape of the 
air in small bubbles and 
insures rapid evaporation. 
The outlet pipe, b 4 , reaches 
only through the stopper. 
Upon the outside of the 
bottle is pasted a paper 
marked with 1-ounce grad- 
uations. C is a piece of 
ordinary f-ineh iron gas 
pipe about 3^ feet long, 
but this may be any de- 
sired length. It is closed 
and roundly pointed at the tip, and for about 15 to 18 inches of its length provided 
with small perforations pointing in all directions to give free escape to the vapor into 
all parts of the sack of seed at once. 

The connections may be of rubber tubing, but as little rubber as possible should be 
used for this apparatus, as it is affected by the vapor of the bisulphid, and the couplings 
will have to be frequently replaced. This, however, will not be a considerable item 
of expense. With the apparatus just described one operator would be able to accom- 
plish the entire work of disinfection. The amount of carbon bisulphid recommended 
is about 1 ounce for each 3-bushel sack. It is safe to say that this can be secured for 
less than 1 cent per ounce when purchased in 25 or 50 pound lots, making the cost of 
bisulphid not over 1 cent per sack. As it requires but from two to three minutes to 
vaporize 1 ounce of the liquid in the manner described, the expense for labor in appli- 
cation would not amount to one-half a cent per sack. Fumigation with carbon bisul- 
phid can therefore be effectively made at the slight expense of from 1 to 1J cents per 
100-pound sack. 

Application of the bisulphid in this manner reduces the elements of danger to a 
minimum, as the vapor is almost wholly confined and the slight quantity escaping, 
mixed with the open air, would not be in either inflammable or explosive proportions. 
It has been determined that the slight trace of bisulphid vapor in the air would not 
injure the operator in the slightest degree. The sacks should be left in the box for 
forty hours after the gas is injected. 




\b 3 S7h/ye</ 



Fig. 34.— Apparatus for fumigating cotton seed in the sack. 
Hunter.) 



(After 



164 THE MEXICAN COTTON-BOLL WEEVIL. 

LEGAL EESTRICTIONS REGARDING THE BOLL WEEVIL. 

UNITED JSTATES STATUTE. 

The statute, quoted in part below, prohibits the interstate ship- 
ment of the boll weevil and certain other insects, and provides 
penalties : 

AN ACT To prohibit the importation or interstate transportation of insect pests, and the use of the 
United States mails for that purpose. 

That no railroad, steamboat, express, stage, or other transportation company shall 
knowingly transport from one State or Territory into any other State or Territory, or 
from the District of Columbia into a State or Territory, or from a State or Territory 
into the District of Columbia, or from a foreign country into the United States, the 
* * * boll weevil, in a live state, or other insect in a live state which is notoriously 
injurious to cultivated crops; * * * or the eggs, pupa? or larva? of any insect 
injurious as aforesaid, except when shipped for scientific purposes under the regula- 
tions hereinafter provided for, nor shall any person remove from one State or Territory 
into another State or Territory, or from a foreign country into the United States, or 
from a State or Territory into the District of Columbia, or from the District of Columbia 
into any State or Territory, except for scientific purposes tinder the regulations herein- 
after provided for, the * * * boll weevil, * * * in a live state, or other 
insect in a live state which is notoriously injurious to cultivated crops; * * * or 
the eggs, pupae or larvse of any insect injurious as aforesaid. (33 Stat. L., 1269.) 

Sec. 2. That any letter, parcel, box, or other package containing the * * * 
boll weevil * * * in a live state or other insect in a live state which is notoriously 
injurious to cultivated crops; * * * or any letter, parcel, box, or package which 
contains the eggs, pupa? or larvae of any insect injurious as aforesaid, whether sealed 
as first class matter or not, is hereby declared to be nonmailable matter, except when 
mailed for scientific purposes under the regulations hereinafter provided for, and 
shall not be conveyed in the mails, nor delivered from any post office, nor by any 
letter carrier, except when mailed for scientific purposes under the regulations here- 
inafter provided for; and any person who shall knowingly deposit, or cause to be 
deposited, for mailing or delivery, anything declared by this section to be nonmail- 
able matter, or cause to be taken from the mails for the purpose of retaining, circulat- 
ing, or disposing of, or of aiding in the retention, circulation or disposition of the same 
shall, for each and every offense, be fined, tipon conviction thereof, not more than 
five thousand dollars or imprisoned at hard labor not more than five years, or both, at 
the discretion of the court: Provided, That nothing in this Act shall authorize any 
person to open any letter or sealed matter of the first class not addressed to himself. 
(33 Stat, L., 1270.) 

Sec. 3. That it shall be the duty of the Secretary of Agriculture and he is hereby 
authorized and directed to prepare and promulgate rules and regulations under 
which the insects covered by sections one and two of this Act may be mailed, shipped, 
transported, delivered and removed, for scientific purposes, from one State or Terri- 
tory into another State or Territory, or from the District of Columbia into a State or 
Territory, or from a State or Territory into the District of Columbia, and any insects 
covered by sections one and two of this Act may be so mailed, shipped, transported, 
delivered and removed, for scientific purposes, under the rules and regulations of the 
Secretary of Agriculture: Provided, That the rules and regulations of the Secretary 
of Agriculture, in so far as they affect the method of mailing insects, shall be approved 
by the Postmaster-General, and nothing in this Act shall be construed to prevent any 
State from making and enforcing laws in furtherance of the purposes of this Act. pro- 
hibiting or regulating the admission into that State of insects from a foreign country. 
(33 Stat. L., 1270.) 

Sec. 4. That any person, company, or corporation who shall knowingly violate the 
provisions of section one of this Act shall, for each offense, be fined, upon conviction 
thereof, not more than live thousand dollars or imprisoned at hard labor not more than 
five years, or both, at the discretion of the court. (33 Stat. L., 1270.) 

QUARANTINES OF THE SEVERAL STATES. 

Quarantines designed to prevent the importation of the boll weevil 
are now in force in the following States and Territories: Alabama, 
California, Georgia, Louisiana, Mississippi, North Carolina, Okla- 



LEGAL RESTRICTIONS. 165 

homa, Porto Rico, South Carolina, Tennessee, and Texas. They 
are directed against all infested counties and States, as well as 
against all counties which may become infested in the future. The 
following pages give the substance of the present restrictions. For 
further particulars the quarantine officers of the several States should 
be addressed directly. 

Alabama. — The present quarantine regulations in Alabama were 
promulgated by the Alabama State board of horticulture on April 
4, 1911. The quarantine applies t<> cotton seed, seed cotton, hulls, 
seed-cotton and cottonseed sacks (which had been used), cotton- 
pickers' sacks, and corn in the shuck. Importation of these articles 
into uninfested territory from infested territory, or from any point 
situated within 20 miles of the area known to be infested, is pro- 
hibited. However, between January 15 and July 15 shipments of 
these articles originating within or ginned within a zone 20 miles 
in length immediately adjoining the infested territory may be made 
to points not more than 40 miles outside of the line of infestation. 
Between October 1 and June 30 shipments of Spanish moss, baled 
or unbaled, originating in infested territory, are prohibited from 
entering or passing through uninfested parts of the State. Cotton 
lint (loose, baled, flat, or compressed) originating in infested locali- 
ties is prohibited except during the months of June, July, and 
August. The shipment of household goods is prohibited unless 
accompanied by an affidavit attached to the waybill to the effect 
that the shipment contains no cotton, cotton seed, seed cotton, 
hulls, seed-cotton and cottonseed sacks, cotton-pickers' sacks, corn 
in the shuck, or loose Spanish moss, except that in shipments of 
household goods made during the months of July, August, and 
September corn shucks or Spanish moss may be used for packing. 
All shipments of quarantined articles must be made in tightly closed 
box cars. No person except the entomologist of the State board of 
horticulture and his deputies is allowed to have in possession outside 
of the weevil-infested territory any live stages of the boll weevil. 
The penalty provided is a tine 'of from $100 to $500. 

Cctiiforma. — In California the boll-weevil quarantine is in the 
form of an order issued by the State commissioner of agriculture 
on April 23, 1908.. This provides that all cotton seed shipped into 
California, shall be consigned through one of the State deputy com- 
missioners of horticulture. These shipments shall be fumigated 
with carbon bisulphid for a period of 24 hours by a deputy com- 
missioner. Deputy commissioners are located at El Centro, San 
Bernardino, Riverside, Los Angeles, and San Diego. 

Florida. — The restrictions in effect are authorized by a statute 
passed in 1911 which established the office of inspector of nursery 
stock. Dr. E. W. Berger, Gainesville, is the present inspector. 

Georgia. — Previous to August 15, 1904, the Georgia State board 
of entomology had authority, by virtue of the legislative act which 
created it, to enact such regulations as it deemed necessary to pre- 
vent the introduction or dissemination of injurious crop pests or 
diseases. On August 28, 1903, this board adopted a regulation 
prohibiting the introduction of cotton seed from Texas except under 
a certificate from an authorized State or Government entomologist 
stating that the seed had been fumigated in such maimer as to kill 
any stage of boll weevils which might be contained therein. On 



166 THE MEXICAN COTTON-BOLL WEEVIL. 

August 15, 1904, an act of the General Assembly of the State of 
Georgia was approved, but further amended August 23, 1905, 
whereby cotton seed, seed cotton, cottonseed hulls, or cotton lint 
in bales or loose, corn in the husk, or all material, including house- 
hold goods packed in any of the above quarantined products, are 
prohibited from being brought into the State except when there is 
attached thereto a certificate signed by an authorized State or 
Government entomologist to the effect that said material was grown 
in and was shipped from a point where, by actual inspection, the 
Mexican cotton-boll weevil was not found to exist. Through ship- 
ments of quarantined articles may be made in cars which must be 
tightly closed, and no unloading is allowed during transit through 
the State. No common carrier shall use for bedding or feed for live 
stock any of the quarantined articles when the shipments originate 
in regions infested with the boll weevil. 

Mr. E. L. Worsham, capitol, Atlanta, is the present quarantine 
official in Georgia. 

Louisiana. — The State entomologist of Louisiana is, by a law passed 
December 15, 1903,» empowered to quarantine against the cotton- 
boll weevil whenever it seems advisable. At present the State is 
entirely infested, but if in the future portions or the State should be 
freed the entomologist is fully empowered to restrict dangerous ship- 
ments into such portions. 

Mr. J. B. Garrett, Baton Rouge, La., is the quarantine officer of 
this State. 

Mississippi. — The State legislature in 1908 passed a law giving the 
entomologist of the experiment station considerable authority in 
regard to the quarantines against the boll weevil. As only part of 
the State is infested, and it may be possible to save certain portions 
several years of injury, the rules established in 1904 should be con- 
sidered in force as restricting shipments into uninfested counties. An 
absolute quarantine is established against cotton seed, seed cotton, 
hulls, seed-cotton and cottonseed sacks (which have been used), 
cotton-pickers' sacks, corn in the shuck, unsacked corn, unsacked 
oats, unsacked wheat, and unsacked cowpeas from the infested terri- 
tory. Through shipments of quarantined articles must be in tightly 
closed cars, which must not be unloaded while in transit through the 
State. Household goods to be shipped from infested territory into 
uninfested parts of the State of Mississippi must be accompanied by 
an affidavit to the effect that no quarantined articles are contained 
as packing or otherwise in the shipment. Baled cotton can be shipped 
into the uninfested parts of the State only in tightly closed cars. 

Prof. R. W. Harned, Agricultural College, Miss., is the quarantine 
o Hicer of this State. 

North Carolina. — -By virtue of authority from the State legislature 
to prevent the importation of crop pests, the North Carolina Crop 
Pest Commission early in 1904 adopted rules establishing a quarantine 
against all localities where the Mexican cotton-boll weevil is known to 
exist. The quarantine was absolute and applied to cotton, cotton 
seed, cottonseed meal, cottonseed hulls, hay, oats, corn, rice, straw, 
rice chaff, and other grain or material likely to harbor any stage of the 
boll weevil. 



LEGAL. RESTRICTIONS. 167 

The rules published in July, 1910, are reproduced verbatim: 

Regulation No. 15. No transportation company, common carrier, or agent thereof, 
shall bring into North Carolina any shipment of seed cotton or cotton-seed hulls origi- 
nating at any point in the States of Texas, Louisiana, Mississippi, Oklahoma and 
Alabama. And this shall likewise apply to other States when the boll weevil shall 
be determined to be established within their borders. 

Regulation No. 1G. Shipments of cotton destined to any points in North Carolina 
and which originate at any point within the States of Texas, Louisiana, Mississippi, 
Oklahoma, Arkansas and Alabama, or other States that may hereafter become infested 
with cotton boll weevil, shall only be in hard compressed bales. If shipped in any 
other form, it is declared to be a public nuisance and is liable to seiz.ure by the Board 
of Agriculture or its agents. 

Regulation No. 17. Any shipment of cotton seed which originates at any point 
in Texas, Louisiana, Mississippi, Oklahoma, Arkansas or Alabama, and which is des- 
tined to any point in North Carolina, can be accepted for transportation only if it 
shall have attached to the bill of lading a certificate or statement signed by a duly 
authorized State or Government Entomologist stating that the point from which said 
shipment originates is a locality not known to be in the area of the boll weevil infection. 

Regulation No. 18. If any shipment of seed cotton, cotton-seed hulls, cotton, or 
cotton seed not in accordance with these regulations be presented to any transporta- 
tion company, common carrier, or agent thereof, for shipment to or delivery at any 
point within this State, same shall be refused, and the case shall be reported to the 
North Carolina State Department of Agriculture, at Raleigh, giving the name and 
address of the consignor and of the consignee. 

Prof. Franklin Sherman, jr., Raleigh, N. C, is the quarantine officer 
in this State. 

Oklahoma. — By virtue of rules and regulations issued by the State 
entomologist in accordance with the laws of the State, shipments of 
cotton seed, cottonseed hulls, seed-cotton and cottonseed sacks, 
cotton-pickers' sacks, and corn hi the shuck are prohibited from infested 
territory into uninfested territory. In the same manner household 
goods are prohibited unless accompanied by a certificate that no 
quarantined material is contained therein. Through shipments of 
quarantined articles shall be made in tightly closed box cars and shall 
not be unloaded while in transit through the State. Shipments of 
baled cotton into uninfested parts shall be made in tightly closed box 
cars. Xo common carrier shall use for bedding or feed for live stock 
any of the quarantined articles which may have originated in infested 
territory. All persons are expressly forbidden to send live weevils in 
any stage to any point in or outside of the State, either by mail, 
express, or otherwise. 

Prof. C. E. Sanborn, Stillwater, Okla., is the quarantine agent for 
this State. 

Porto Rico. — By legislative act no cotton seed, seed cotton, cotton 
lint, loose or in bales, shall be brought into the island of Porto Rico, 
from any State or county whatsoever without being accompanied 
by the certificate of a duly authorized State or Federal entomologist 
that the shipment originated in a locality where, by actual inspection 
of such official or his agent, the boll weevil was not found to exist. 
Shipments not so certified are liable to seizure and destruction. 
Punishment is provided for in section 16 of the Penal Code of Porto 
Rico of 1902. 

The governor of the island lias direct control over the enforcement 
of this law. 

South Carolina. — In South Carolina the quarantine regulations are 
entirely embodied in the laws of the State, and consequently not so 
readily modified to conform with the changed conditions and a better 
understanding of the methods of dissemination of the boll weevil as 



168 THE MEXICAN COTTON-BOLL WEEVIL. 

is the case when authority to promulgate rules and regulations is 
invested in a commission or in the State entomologist. The law 
established to guard against 'the introduction of the Mexican boll 
weevil into the State of South Carolina was approved on February 25. 
1904. The commodities quarantined against were cotton seed, oats, 
and prairie hay, shipped directly or indirectly from infested points 
in the State of Texas. 

Prof. A. F. Conradi, Clemson College, S. C, can furnish information 
concerning the interpretation of the State law. 

Tennessee. — In compliance with the requirements of an act of the 
General Assembly of the State of Tennessee (S. B. No. 442, chap. 466), 
approved April 17, 1905, entitled "An act to create aState entomologist 
and plant pathologist," etc., the State board of entomology, estab- 
lished by said act, announced the following rules and regulations 
under date of December 31, 1910. 

(a) No cotton lint (loose, baled, flat, or compressed), cotton seed, seed cotton, 
cotton-seed hulls, seed-cotton or cotton-seed sacks (which have been used), or corn in 
the shuck, shall be shipped into Tennessee from the infested territory of Texas, Okla- 
homa, Louisiana, Arkansas and Mississippi. 

(6) Shipments of household goods from infested areas of above named States shall 
not be admitted into Tennessee unless accompanied by an affidavit attached to the 
way-bill to the effect that the shipment contains no cotton lint, cotton seed, seed 
cotton, cotton-seed hulls, seed-cotton or cotton-seed sacks, or corn in the shuck. 

(c) It shall be unlawful for anyone in Tennessee to have in his possession live Mexi- 
can cotton boll weevils. The public is urged to recognize the danger of introducing 
unwittingly live boll weevils for inspection, observation, or experiment. 

Mr. G. M. Bentley, Knoxville, Tenn., is the officer in this State. 

Texas. — In accordance with an act of the State legislature, to pre- 
vent the spread and dissemination of injurious insects, the commis- 
sioner of agriculture designated the boll weevil as such an insect to be 
quarantined. This ruling in the act makes it illegal to ship seed cot- 
ton or cotton seed, or any other article which might carry the boll 
weevil from an infested county to an uninfested county. 

Mr. Ed. R. Kone, Austin, Tex., is the State officer charged with 
quarantine enforcement. 

Regulations of foreign governments. — The Governments of Egypt, 
Peru, and India have established an injunction against the importa- 
tion of American cotton seed originating in the infested localities. 
In all cases, however, it can be arranged to have shipments cleared in 
case they are accompanied b} r certificates of fumigation by a com- 
petent authority. 



THE MEXTCAN COTTON-BOLL WEEVIL. 169 



BIBLIOGRAPHY. 

This bibliography includes only the more important writings which 
have been published in permanent form. In the preliminary part 
of this bibliography a special synopsis is given of the contents of pub- 
lications, more particularly to outline the history of the cultural 
method now recognized as of supreme importance in the control of 
the boll weevil. No attempt is made to give a synopsis of the later 
titles. For a complete annotated bibliography see Circular No. 140, 
Bureau of Entomology. 

1843. Boheman, C. IT. — Genera et species Curculionidum cum synonymia hujus 
i'amilise ed. C. J. Schonherr, vol. 5, pt. 2, pp. 232-233. 

The original description of Anthonomus grandis. 

1871. Suffrian, E. — Verzeichniss dervon Dr. Gundlaeh auf derlnselCuba gesam- 
melten Riisselkafer.<Archiv f. Naturg., vol. 37, Jahrg. 13, pt. 1, pp. 130-131. 
Contains the record of a specimen from Cardenas and one from San Cristobal, in Cuba. 
1885. Riley, C. V. — Report of the Commissioner of Agriculture for 1885, p. 279. 

Contains the sentence "Another very large species, A . grandis Boh., we have reared at this depart- 
ment from dwarfed cotton bolls sent from northern Mexico by Dr. Edward Palmer." This is the 
lirst published record of the food plant and method of injury of the species. 

1891. Dietz, W. G. — Revision of the genera and species of Anthonomini inhabiting 
North America. <Trans. Amer. Ent. Soc, vol. 18, p. 205. 

l'he species is here reported from Texas. It has teen shown, however, that this was an error. 
(See Insect Life, vol. 7, p. 27:?.) 

1891. Gundlach, Juan. — Contribucion a la entomologia Cubana, vol. 3, pt. 5, p. 285. 

'i -i:t ions occurrence in Cuba. 

1894. Howard, L. O. — A new cotton insect in Texas. <Ins. Life, vol. 7, p. 273. 

The first authentic account of the occurrence of the species in the United States, and some state- 
ments regarding its life history. 

1895. Howard, L. O. — The new cotton-boll weevil. <Ins. Life, vol. 7, p. 281. 
1895. Townsend, <\ II. T. Report on the Mexican cotton boll weevil in Texas 

(Anthonomus grandis Boh.). <!ns. Life, vol. 7, no. 4, pp. 29.") 309, tigs. 30, 
31, March. 

An important preliminary pap r giving valuable data on life history and habits, an account of its 
spread from Mexico to Texas, and its extent in Texas at that time In the consideration of remedies 
are suggested die cutting and burning over of the cotton fields in winter, the abandonment of cot ion 
growing over the region then infested, and the maintenance of a w ide zone free from cotton along the 
lower Rio Grande bordering Mexico, with other suggestions of less practical value. 

1895. Howard, L. O. — The Mexican cotton-boll weevil. <('ir. 6 (second series), 
Div. Ent., U. S. Dept. Agr., pp. 5, figs. 1 3, April. 

This circular gives the results, substantially, of Mr. Townsend 's field investigations of the insect in 
Mexico and Texas, The impracticability of the use of poisons is shown, and the collection and 
destruction of infested bolls and rotation of crops are suggested. English and Spanish edit ions were 
issued. 

1895. Rios, J. R. — Aparicion del "picudo" en la Laguna.<El Progreso de Mex., 

Aug. 15, 1895. Reprinted in vol. 4, pp. 811-813, 1897. 

1896. Howard, 1.. O. — The Mexican cotton-boll weevil. <<ir 14 (second scries), 

Div. Ent., U. S. Dept, Agr., pp. 8, figs. 1-5. 

Contains a large amount of additional information relative to distribution, natural history and 
habits, and natural enemies and parasites, now worked out with substantial accuracy. Under tin' 
head of remedies is the first suggestion of the great importance of the cultural method of control, 
and especially the early fall destruction of the cotton plants, together with the recommendation of 
early planting and clean cultivation. Trapping late beetles in fall and o\ er-wintered beetles in early 
spring is advised, together with the destruction of volunteer plants, the region infested up to this 
time being burly within the range of volunteer or seppa cotton. 



170 THE MEXICAN COTTON-BOLL WEEVIL. 

1897. Howard, L. O. — The Mexican cotton-boll wevil.<Cir. 18 (second series), 
Div. Ent., U. S. Dept. Agr., pp. 8, figs. 1-5. 

This circular brings the data on distribution and other features down to date, and in the matter 
of remedies incorporates the results of field studies in Texas by Mr. ('. L. Marlatt on food habits 
ami poisoning, and indicates the supreme importance of the cultural method of control, all other 
steps being merely palliative or to offset the failure to adopt this method. Issued in English, Span- 
ish, and German editions. 

1897. Junta de defensa contra el "picudo." (Editorial. )<E1 Progreso de Mex., 
vol. 5, pp. 8-9, Oct. 8. 

1897. El picudo (Anthonomus grandis Boh .) . (Editorial.)<Documentosreferentesa 

su existencia en Mexico y a su invasion in los Estados Unidos del Norte. 

Mexico Oficina Tip. de la Secretaria de Fomento, pp. 100, figs. 1-5. 
1897. Balestrier, L. de. — Las medias precautorias contra las plagas queasolan a la 

agricultura.<El Progreso de Mex., vol. 4, pp. 575-576, May 22. 
1897. Howard, L. O. — The Mexican cotton-boll weevil in 1897. Cir. 27 (second 

series), Div. Ent., U. S. Dept. Agr., pp. 7. 

This circular records more particularly the further spread of the weevil, and repeats the sugges- 
tions relative to the cultural method of control from Circular 18, which method is urged as a prac- 
tically complete remedy for the insect. 

1897. Howard, L. O. — Insects affecting the cotton plant. <Farm. Bull. 47, U. S. 

Dept. Agr., pp. 16-23, figs. 7-11. 

Reprinted from Bulletin 33, Office of Experiment Stations, V. S. Dept. Agr., pp. 317-350. 

1898. Howard, L. 0. — Remedial work against the Mexican cotton-boll weevil. <Cir. 

33 (second series), Div. Ent., U. S. Dept. Agr., pp. 6. 

This is a supplementary circular giving the results of some experiments with poisons by Mr. Mar- 
latt and Mr. Townsend. The cultural system of control is, however, again insisted upon. 

1901. Rangel, A. F. — Estudios preliminares acerca del picudo del algodon (Insan- 
thonomus grandis I. C. Cu.).<Boletin de la Comision de Parasitologia Agri- 
cola, vol. 1, no. 3, pp. 93-104, pi. 9 and figure. 

Deals with 45 experiments regarding destruction by means of hot air, hot water, steam, hapla- 
phyton, and arsenic. 

1901. Mally, F. W. — A preliminary report of progress of an investigation concern- 
ing the life history, habits, injuries, and methods for destroying the Mexican 
cotton-boll weevil (Anthonomous (sic) grandis). Authorized by special Act 
of the Twenty-sixth Legislature of Texas, pp. 1-30, supplement pp. 35-45. 

1901. Mally, F. W.— The Mexican cotton-boll weevil. <Farm. Bull. 130, U. S. 
Dept. Agr., pp. 30, figs. 1-4. 

A reprint, with minor corrections, of the preceding, excepting the supplement. Contains much 
new valuable information, but in the subject of remedies represents Mr. Mally's own point of view 
and not the advice of the bureau current at the same time. Nevertheless, the cultural method is 
again given the greatest prominence. 

1901. Rangel, A. F. — Segundo informe acerca del picudo del algodon (Insanthono- 

mus grandis I. C. Cu.).<Boletin de la Comision de Parasitologia Agricola, 

vol. 1, no. 5, pp. 171-176. 
1901. Rangel, A. F. — Tercer informe acerca del picudo del algodon. <Boletin de 

la Comision de Parasitologia Agricola, Mexico, vol. 1, no. 6, pp. 197-206. 
1901. Rangel, A. F. — Cuarto informe acerca del picudo del algodon (Insanthonomus 

grandis I. C. Cu.).<Boletin de la Comision de Parasitologia Agricola, vol. 

1, no. 7, pp. 245-261, pis. 16, 23. 

1901. Rangel, A. F. — -Quinto informe acerca del picudo del algodon. <Boletin de 

la Comision de Parasitologia Agricola, Mexico, vol. 1, no. 8, pp. 302-317. 

1902. Ashmead, W. H. — A new Bruchophagus from Mexico. <Psyche, vol. 9, p. 

324, March. 

Contains the description of Bruchophagus herrerx n. sp., a parasite of Anthonomus grandis, from 
Coahuila, Mexico. 

1902. Rangel, A. F. — Sexto informe acerca del picudo del algodon. <Boletin de 
la Comision de Parasitologia Agricola, Mexico, vol. 1, no. 9, pp. 403407. 

1902. Etjnter, W. D. — The present status of the Mexican cotton boll weevil in the 
United States. < Yearbook V . S. Dept. Agr. for 1901, pp. 369-380, 1 fig. 

In this publication the cultural method of control is substantially the only method recommended, 
augmented by the suggestion of securing northern seed and early maturing varieties to hasten the 
c i op production; also suggests the wide spacing of rows to secure the same end. 

1902. Mally, F. W— Report on the boll weevil. Pp. 70, figs. 3. Austin, State 
Printer. 



BIBLIOGRAPHY. 171 

1902. Madero, J. M. C. — Una plaga del algodon.<Boletin de Agricultura. (Sal- 

vador) vol. 2, no. 11, pp. 483-485, duly 15. 

Comments on failure of means of control as then recommended by the United States Department 
df Agriculture. States thai cotton growing has been abandoned on account of the weevil in Coa- 
liuila. for corn and wheal . 

1903. Hunter, W. D.— Methods of controlling the boll weevil (advice based on the 

work of 1902).<Farm. Bui. 163, U. S. Dept. Agr., pp. 16, figs. 2, January. 

The reoammendal ions as to the steps of the cultural method arc repeated in this publical ion, with 

the added suggestion of thorough cultivation and thinning of plants in the rows as well as wide 
spacing to hasten maturity. 

1903. Barreda, L. de la. — El picudo en San Pedro de la Colonia.< Bole tin de la 
Comision de Parasitologia Agricola, Mexico, vol. 2, no. 2, pp. 45-58. 

1903. Sanderson, E. D— The Mexican boll weevil.<Cir. 1, Ent. Dept., Tex. 
Agr. Exp. Sta., no. 1. Press Notes, vol. 5, no. 3, pp. 8, figs. 4, February. 

1903. Kill the boll weevil. How to grow cotton in the weevil district. History of 
the pest, its habits, and the remedies plainly disclosed. l'p. X, figs. 4. Pub- 
lished by the Executive Committee of the Texas Boll Weevil Convention. 

1903. Champion, G. C. — Biologia Centrali- Americana. Coleoptera, vol. 4, pt. 4, p. 
L86, pi. 11, figs. 3, 3a, April. 

1903. Save the cotton crop. Testimony of cotton growers on boll weevil. How to 
insure the cotton crop in the weevil district. Pp. 16. Published by the 
Executive Committee of the Texas Boll Weevil Convention, Bui. No. 2, 
May. Also published in German under the title, "Rettet die Baumwolle," 
and in Bohemian under the title. "Zachrante bavlnu." 

1903. Sanderson, E. D. — How to combat the Mexican cotton-boll weevil in summer 
and fall.<Cir. 4, Ent. Dept., Tex. Agr. Exp. Sta. Press Notes, vol. 5, no. 
1, pp. 4, August 10. 

1903. Improved cotton seed for Texas planting. Published by the Executive Com- 
mittee of the Texas Boll Weevil Convention, pp. 32. Bui. No. 4, Novem- 
ber 9; revised November 17. 

1903. Morgan, H. A. — The Mexican cotton boll weevil. Cir. 1, La. Agr. Exp. Sta., 
pp. 10, figs. 3, map 1, November. 

1903. Wilson, James.— Report of the Secretary of Agriculture, 1903. Pp. 102-106 
under heading, "Crisis in cotton production," deals with the boll-weevil 
problem, December. 

1903. Connell, J. H. — Proceedings of the second annual session Texas cotton grow- 
ers' convention, Dallas, Tex. Pp. 99; many illustrations, December. 

1903. Proceedings of the boll weevil convention called by Governor W. W. Heard in 

Xew Orleans, La., November 30 and December 1. Issued by Louisiana 
Bureau of Agriculture and Immigration. 

1904. Schwarz, E. A.— The cotton boll weevil in Cuba.<Proc. Ent. Soc. Wash., 

vol. 6, pp. 13-17, January 15. 

Report upon investigations regarding the abundance of this species; food plants and parasites in 

Cuba. 

L904. Herrick, G. W. — The Mexican cotton boll weevil. <Cir. 17, Miss. Agr. Exp. 

Sta., pp. 7, figs. 2, February. 
1904. Hunter, W. D. — Information concerning the Mexican cotton boll weevil. 

<Farm. Bui. No. 189, U. S. Dept. Agr., pp. 1-31, figs. 1-8, February. 
L904. Sanderson, E. D— The cotton boll weevil in Texas. <('ir. 8, Ent. "Dept., 

Tex. Agr. Exp. Sta., pp. 14, figs. 6, April 15. 
1D04. Hunter, W. D.— The status of the Mexican cotton boll weevil in the United 

States in 1903. < Yearbook U. S. Dept. Agr. for 1903, pp. 205-214, pis. 17, 18, 

19, 20, 21, figs. 10, map 1. 
1904. Hunter, W. I)., and Hinds, W. E. — The Mexican cotton boll weevil. <Bul. 45, 

Div. Ent., U. S. Dept. Agr., pp. 1-116, pis. 1-16, figs. 1-0, May 19. 
1904. Cook, O. F.— An enemy of the cotton boll weevil. <U. S. Dept. Agr., Rept. 78, 

office of the Secy., pp. 7. Issued May 27. 
1904. Morgan, H. A.— The Mexican cotton "boll weevil. <Cir. 1, State Crop Pest 

Comm., La., pp. L6, figs. 3, June 1. 
1H04. Cook, O. F. — Report on the habits of the kelep, or Guatemalan cotton boll 

weevil ant. <Bul. 49, Bur. Ent., U. S. Dept. Agr., pp. 15, July 26. 
L904. Wilcox, E. M.— The Mexican cotton boll weevil. <Bul. 129, Ala. Agr. Exp. 

Sta., pp. 91-104, figs. 1-4, August. 



172 THE MEXICAN COTTON-BOLL WEEVIL. 

1904. Hunter, W. D.— Controlling the boli weevil in cotton seed and at ginneries. 

<Fann. Bui. 209, U. S. Dept, Agr., pp. 31, fig. 1, September 16. 
1904. Sanderson, E. D. — Insects mistaken for the Mexican cotton boll weevil. <Bul 

74, Tex. Agr. Exp. Sta., pp. 12, figs. 13, September. 
1904. Newell, Wilmon.— The Mexican cotton boll weevil. <Bul. 12, Ga. St. Bd. 

Ent., pp. 29, figs. 21, September. 
1904. Hunter, W. D. — The most important step in the cultural system of controlling 

the boll weevil. <Cir. 56, Bur. Ent., U. S. Dept. Agr., pp. 6, October 10. 
1904. Hunter, W. D. — The use of Paris green in controlling the cotton boll weevil. 

<Farm. Bui. 211, U. S. Dept. Agr., pp. 23, December 5. 

1904. Proceedings of the second annual meeting Louisiana boll weevil convention, 

held at Shreveport, La., November 3 and 4, 1904. Issued by the State 
Board of Agriculture and Immigration. 

1905. Sherman, Franklin, Jr. — The cotton boll weevil. <Ent. Cir. 14, N. C. Dept. 

Agr., pp. 11, figs. 5, January 20. 

1905. Hunter, W. D. — The control of the boll weevil, including results of recent 
investigations. <Farm. Bui. 216, U. S. Dept. Agr., pp. 32, figs. 1-5, March. 

1905. Hunter, W. D. — Present status of the cotton boll weevil in the United States. 
<Yearbook U. S. Dept. Agr. for 1904, pp. 191-204, 2 pis., 1 fig. 

1905. Hunter, W. D. and Hinds, W. E. — The Mexican cotton boll weevil. A revi- 
sion and amplification of Bulletin 45 to include the most important observa- 
tions made in 1904. <Bul. 51, Bur. Ent,, U. S. Dept, Agr., 181 pp., 23 pis., 
8 figs. 

1905. Cook, O. F. — The social organization and breeding habits of the cotton-pro- 
tecting kelep of Guatemala, <Tech. Ser. 10, Bin. Ent,, U. S. Dept. Agr., 
55 pp. 

1905. Redding, R. J. — Essential steps in securing an early crop of cotton. <Farm. 
Bui. 217, U. S. Dept. Agr. 

1905. Bailey, Vernon. — Birds known to eat the boll weevil. <Bul. 22, Bur. Biol. 
Surv., U. S. Dept. Agr., 16 pp. 

1905. Sanderson, E. D. — Some observations on the cotton boll weevil. <Bul. 52, 
Bur. Ent., U. S. Dept. Agr., pp. 29-42, 1 fig. 

1905. Newell, Wilmon. — The remedy for the boll weevil. <Cir. 3, State Crop Pest 

Commission of Louisiana, 20 pp., 5 figs., November. Revised edition: 1906, 
March, 23 pp., 5 figs. 

1906. Cook, O. F. — Weevil-resisting adaptations of the cotton plant. <Bul. 88, Bur. 

Plant Ind., U. S. Dept. Agr., 87 pp., 10 pis., January 13. 
1906. Newell, Wilmon. — The work of the State crop pest commission with the boll 

weevil. <Cir. 5, State Crop Pest Commission of Louisiana, 20 pp., 3 figs., 

January. 
1906. Champion, G. C. — Biologia Centrali Americana. Coleoptera, vol. 4, pt. 4, 

p. 722, April. 

Boll weevil recorded from San Jose, Costa Rica. 

1906. Newell, Wilmon. — The boll weevil. Information concerning its life history 

and habits. <Cir. 9, State Crop Pest Commission of Louisiana, 29 pp., 15 

figs., July. 
1906. Howell, A. H. — Birds that eat the cotton boll weevil. A report of progress. 

<Bul. 25, Bur. Biol. Surv., U. S. Dept. Agr., 22 pp. 
1906. Cook, Mel. T. — Insectos y enfermedades del algodon.<Trimer informe anual 

de la Estacion Central Agronomica de Cuba, pp. 178-180, 1 fig. 
1906. Barreda L. de la. — Anotaciones al "Boletin de los agricultores," number 

216, de la Secretaria de Agricultura de los Estados Unidos.<Cir. 32, Comision 

de Parasitologia Agricola, Mex., pp. 42-48. 
1906. Hinds, W. E. — Proliferation as a factor in the natural control of the Mexican 

cotton boll weevil. <Bul. 59, Bur. Ent., U. S. Dept. Agi., 45 pp., 6 pis., 11 

tables, August 27. 
1906. Sanderson, E. D. — National control of introduced insect pests. <Bul. 60, 

Bur. Ent., U. S. Dept. Agr., p. 99, September 22. 
1906. Hinds, W. E. — Laboratory methods in the cotton boll weevil investigations. 

<Bul. 60, Bvir. Ent,, U. S. Dept. Agr., pp. 111-119, 2 pis., September 22. 
1906. Howard, L. O., and Burgess, A. F. — The laws in force against injurious 

insects and foul brood in the United Slates. <Bul. 61, Bur. Ent., U. S. Dept, 

Agr., pp. 9, 34-35, 38-39, 55-60, 79-80, 108-109, 117-119, 128, 134, 139-141, 

145, November 5. 
All State laws against the boll weevil in force at the time of publication are given in full. 



BIBLIOGRAPHY. 173 

1907. Sanderson, E. D. — Hibernation and development of the cotton boll weevil. 

<Bul. 63, Bur. Ent., U. S. Dept. Agr., pt. 1, 38 pp., 6 figs., January 15. 
1907. Flynn, C. W., Jr. — The boll weevil. <(_'ir. 11, State Crop Pest Commission 

of Louisiana, 19 pp., 2 figs., January. 
Report on the cultural experiments in cooperation with the Bureau of Kntomology during 1906. 

1907. Hinds, W. E. — An ant enemy of the cotton boll weevil. <Bul. 63, Bur. Ent., 
U. S. Dept. Agr., pt. 3, pp. 45-48, 1 fig., February 5. 

1907. Morgan, A. C. — A predatory bug reported as an enemy of the cotton boll wee- 
vil. Papers on the cotton boll weevil and related and associated insects. 
<Bul. 63, Bur. Ent., U. S. Dept. Agr., pt. 4, pp. 49-54, figs. 8-9, February 8. 
Life history and habits of a bug, Apiomerus spissipes Say, reported as an enemy of the boll weevil. 

1907. Hunter, W. D. — Some recent studies of the Mexican cotton boll weevil. 

<Yearbook, U. S. Dept. Agr., for 1906, pp. 313--324, 1 pi., 1 map. 
1907. Flynn, C. \V., Jr. — Experiments in the late planting of cotton to avoid boll 

weevil damage, during 1906. <Bul. 92, La. Agr. Exp. Sta., 8 pp., May. 
1907. Crawford, J. C. — New hymenopterous parasites of Anthonomus grandis 

Boh.<Can. Ent., vol. 39, pp. 133-134, April. 

Original description of Torymus anthonomi, Urosigalphus anthonomi, and Urosigalphus schwarzi, 
all reared from the boll weevil. 

1907. Newell, Wilmon. — Report upon the work of the State Crop Pest Commission 
<Cir. 13, State Crop Pest Commission of Louisiana, pp. 4-5, April. 

1907. Newell, Wilmon. — Fighting the boll weevil by picking up the infested 
squares. <Cir. 15, State Crop Pest Commission of Louisiana, 4 pp., June. 

1907. Mayer, August. — The most important factor in solving the boll weevil 
problem. <Cir. 16, State Crop Pest Commission of Louisiana, 8 pp., June 20. 

Discussion of the relation of the cattle tick to the boll weevil problem. Particular stress is placed 
upon the necessity of eradicating the cattle tick so as to enable the cotton growers of the South to 
raise cattle profitably and thus have the manure to increase the productivity of the soil. 

1907. Newell, Wilmon. — The State Crop Pest Law of Louisiana and rules and 

regulations of the State Crop Pest Commission, in effect July 1, 1907. <Cir. 

17, State Crop Pest Commission of Louisiana, 19 pp., July. 
1907. Pierce, W. D. — On the biologies of the Rhynchophora of North America. 

<Ann. Rept. Nebr. St. Bd. Agr., pp. 269, 295-307, 1 pi. 
1907. Herrick, G. W.— The boll weevil. <Cir. Miss. Agr. Exp. Sta., 7 pp., 1 fig., 

September. 
1907. Hunter, W. D. — The most important step in the control of the boll weevil. 

<Cir. 95, Bur. Ent., U. S. Dept. Agr., 8 pp., October 13. 
L907. Hunter, W. D., Newell, Wilmon, and Pierce, W. D. — The insect enemies 

of the cotton boll weevil. <Cir. 20, State Crop Pest Commission of Louisiana, 

7 pp., 3 figs., December. 
1907. Hinds, W. E. — Some factors in the natural control of the Mexican cotton boll 

weevil. <Bul. 74, Bur. Ent., U. S. Dept. Agr., 79 pp., 4 pis., 2 figs., 17 tables, 

December 14. 
1907. Howell, A. H.— The relation of birds to the cotton boll weevil. <Bul. 29, 

Bur. Biol. Surv., U. S. Dept. Agr., 31 pp., 1 pi., 6 figs. 
1907. Barreda, L. de la. — Las plagas del algodonero.<Boletin de la Comision de 

Parasitologia Agricola, Mex., vol. 4, no. 2, pp. 107-215, 24 pis., 1 map. 

1907. Henshaw, H. W. — Birds useful in the war against the cotton boll weevil. 

<Cir. 57, Bur. Biol. Surv., U. S. Dept. Agr., 4 pp. 

1908. Pierce, W. D. — Studies of parasites of the cotton boll weevil. <Bul. 73, Bur. 

Ent., U. S. Dept. Agr., 63 pp., 3 pis., 6 figs., January 21. 
1908. Bennett, R. L. — A method of breeding early cotton to escape boll weevil 

damage. <Farm. Bui. 314, U. S. Dept. Agr., pp. 30, figs. 1-16, February 17. 
1908. Sherman, Franklin, Jr. — Erroneous reports of cotton boll weevil — its 

present status. <Ent. Cir. 21, N. Car. Dept Agr., 4 pp., March. 
1908. Newell, Wilmon. — The boll weevil. ^Second Bien. Rept. Sec. State Crop 

Pest Commission of Louisiana for the years 1906-1907, pp. 9-16; also an 

appendix. 
1908. Knapp, S. A. — Demonstration work in cooperation with southern farmers. 

<Farm. Bui. 319, U. S. Dept. Agr., 22 pp., April 6. 
1908. Newell, Wilmon, and Paulsen, T. C. — The possibility of reducing boll 

weevil damage by autumn spraying of cotton fields to destroy the foliage 

and squares. <Journ. Econ. Ent., vol. 1, pp. 113-117, April 15. 
1908. Pierce, W. D. — The economic bearing of recent studies of the parasites of the 

cotton boll weevil. <Joum. Econ. Ent., vol. 1, pp. 117-122, April 15. 



174 THE MEXICAN COTTON-BOLL WEEVIL. 

1908. Crawford, J. C. — Some new Chalcidoidea.<Proc. Ent. Soc. Wash., vol. 9, 
pp. 157-160, April 25. 

Original descriptions of Cerambycdbius cushmani and Catolaccus hunter i, reared from the cctton 
boll weevil. 

1908. Newell, Wilmon, and Rosenfeld, A. H. — A brief summary of the more 

important injurious insects of Louisiana. <Journ. Econ. Ent., vol. 1, p. 151, 

April 15. 
1908. Newell, Wilmon. — The early cotton and the boll weevil. <Cir. 22, State 

Crop Pest Commission of Louisiana, 7 pp., May. 
1908. Howell, A. H. — Destruction of the cotton boll weevil by birds in winter. 

<Cir. 64, Bur. Biol. Surv., U. S. Dept. Agr., 5 pp., 1 map, June 19. 
1908. Newell, Wilmon, and Barber, T. C. — Preliminary report upon experiments 

with powdered arsenate of lead as a boll weevil poison. <Cir. 23, State Crop 

Pest Commission of Louisiana, pp. 9-40, 3 figs., July. 
1908. Hinds, W. E. — The first and last essential step in combating the boll weevil. 

<Journ. Econ. Ent., vol. 1, no. 4, pp. 233-243, August 15. 
1908. Newell, Wilmon, and Trehearne, R. C. — A new predaceous enemy of the 

boll weevil. <Journ. Econ. Ent., vol. 1, p. 244, August 15. 

Note of the destruction of adult boll weevils by the carabid beetle, Evarthrus sodalis Le C, as also 
by another species of Evarthrus. 

1908. Newell, Wilmon. — Destroying the boll weevils before they enter hibernation. 
<Cir. 24, State Crop Pest Commission of Louisiana, pp. 41-48, August. 

1908. Pierce, W. D. — Factors controlling parasitism with special reference to the 
cotton boll weevil. <Journ. Econ. Ent., vol. 1, pp. 315-323, October 15. 

1908. Pierce, W. D. — A list of parasites known to attack American Rhynchophora. 
<Journ. Econ. Ent., vol. 1, pp. 380-396, December 15. 

1908. Hutchinson, W. L. — Cotton culture in Mississippi in areas infested with the 
Mexican cotton boll weevil. <Bul. 117, Miss. Agr. Exp. Sta., 6 pp., Decem- 
ber. 

1908. Hunter, W. D. — The cotton boll weevil in Oklahoma. <First Bien. Rept., 

Okla. St. Bd. Agr. to the Legislature of the State, for the years 1907-08, 
part 5, pp. 36-12. 

1909. Hunter, W. D. — What can be done in destroying the cotton boll weevil dur- 

ing the winter. <Cir. 107, Bur. Ent., U. S. Dept. Agr., 4 pp., January 12. 
1909. Hunter, W. D. — The boll weevil problem with special reference to means of 

reducing damage. <Farm. Bui. 344, U. S. Dept. Agr., 46 pp., 9 figs., January 

23. 
1909. Bennett, R. L. — Growing cotton under boll weevil conditions. <Bul., Miss. 

Agr. and Mech. Coll., Farm. Inst. Dept., vol. 6, no. 1, 13 pp., January. 
1909. Newell, Wilmon. — What constitutes a perfect stand of cotton when fighting 

the boll weevil?<Special Boll Weevil Bui. 1, La. St. Bd. Agr. and Immig. 

Cir. 25, State Crop Pest Commission of Louisiana, 15 pp. 
1909. Newell, Wilmon, and Rosenfeld, A. H. — Report upon variety and fertilizer 

experiments with cotton in the boll weevil infested sections of Louisiana. 

<Cir. 26, State Crop Pest Commission of Louisiana, pp. 65-86, February. 
1909. Hinds, W. E. — Facing the boll weevil problem in Alabama. <Bul. 146, Ala. 

Agr. Exp. Sta., pp. 81-102, 2 pis., 1 fig., June. 
1909. Newell, Wilmon, and Dougherty, M. S. — The "V" cotton-stalk cutter. 

How to make it and how to use it.<Cir. 30, State Crop Pest Commission of 

Louisiana, pp. 151-158, 4 figs., September 15. 
1909. Newell, Wilmon, and Dougherty, M. S. — The hibernation of the boll weevil 

in central Louisiana. <Cb. 31, State Crop Pest Commission of Louisiana, 

pp. 163-219, 6 figs., October. 
1909. Hinds, W. E., and Yothers, W. W. Hibernation of the Mexican cotton boll 

weevil. <Bul. 77, Bur. Ent.,U. S. Dept. Agr., 106 pp., 10 pis., 9 figs., October 

18. 

1909. Newell, Wilmon, and Smith, G. D. — Experiments with powdered arsenate of 

lead as a practical boll weevil po.'son.<Cir. 33, State Crop Pest Commission 
of Louisiana, pp. 251-333, 4 figs. 

1910. Hunter, W. D.— The status of the boll weevil in 1909. <Ch. 122, Bui. Ent. 

U. S. Dept. Agr., 12 pp., 1 fig. 
1910. Harned, R. W— Boll weevil in Mississippi, 1909. <Bul. 139, Miss. Agr. Exp. 

Sta., 43 pp., 28 figs., March. 
1910. Pierce, W. D. — On some phases of parasitism displayed by insect enemies of 

weevils.<Journ. Econ. Ent., vol. 3, no. 6, pp. 451-458, December 15. 



BIBLIOGRAPHY. 175 

1911. Bishopp, F. C. — An annotated bibliography of the cotton boll weevil. <Cir. 

140, Bur. Ent. U. S. Dept. Agr., June 14. 
1911. Pierce, W. D. — Some factors influencing the development of the boll weevil. 

<Proc. Ent. Soc. Wash., vol. 13, pp. 111-117, June 19. 
1911. Rosenfeld, A. H. — Insects and spiders in Spanish moss.<Journ. Econ. Ent., 

vol. 4, no. 4, pp. 398-409. 

1911. Cushman, R. A. — Studies in the biology of the boll weevil in the Mississippi 

Delta region of Louisiana. <Journ. Econ. Ent., vol. 4, no. 5, pp. 432-448, 
October 16. 

1912. Hunter, W. D. — The movement of the Mexican cotton boll weevil in 1911. 

<Cir. 146, Bur. Ent., U. S. Dept. Agr., 4 pp., 1 fig. (map), February 12. 
1912. Pierce, W. D. — Systematic notes and descriptions of some weevils of economic 

or biological importance. <Proc. U. S. Nat. Mus., vol. 42, no. 1889, pp. 

155-170. 
1912. Pierce, W. D., Cushman, R. A., and Hood, 0. E. — The insect enemies of the 

cotton boll weevil. <Bul. 100, Bur. Ent. U. S. Dept. Agr., pp. 99, pis. 3, 

figs. 26, March 15. 



INDEX 



A.camatus commutatus. (See Eciton [Acamatus]commutatu8.) Page. 

A ruins attacked by Balaninus nasicus 30 

Conotrachclus naso 30 

of live oak attacked by Balaninus victoriensis 30 

Agelaius phamiceus, enemy of boll weevil 146 

Alabama argillacea (see also Leaf worm). 

effect on boll-weevil dispersion 87 

enemy of boll weevil 138-139 

cotton 15 

periodical abundance 83 

Althaea sp. (see also Hollyhock). 

tested as food plant of boll weevil 32 

Altitude, effect on boll weevil 28-29 

Amaranthus (see also Pigweed). 

hybridus tested as food plant of boll weevil 32 

spinosus tested as food plant of boll weevil 32 

Ambrosia psilostachya tested as food plant of boll weevil 32 

roots attacked by Baris striata 30 

stems attacked by Lixus scrobicollis 30 

Ant, Argentine. (See Iridomyrmex humilis.) 
lion. (See Dorymyrmcx ptjramicus.) 

Anthonomus albopilosus attacks seed pods of wild sage (Croton) 30 

mistaken for boll weevil 30 

eugen ii attacks pepper pods 30 

mistaken for boll weevil 30 

fulvus attacks purple mallow buds SO 

mistaken for boll weevil 30 

grandis. (See Boll weevil.) 

signatus attacks blackberry, dewberry, and strawberry buds 30 

mistaken for boll weevil 30 

vestitus attacks cotton squares in Peru 30 

Anthribus cornutus attacks cotton stems 30 

mistaken for boll weevil 30 

Anthus pensilvanicus, enemy of boll weevil 1 Hi 

A }>h iochpeta fasciata , enemy of boll weevil 1)2 

nigriceps, enemy of boll weevil 142 

pygmsea, enemy of boll weevil 142 

Apiomerus spissipes, enemy of boll weevil 137 

Arsecerus J'asciculutus attacks china-berries, coffee beans, and old cotton bolls.. 30 

breeds in old dried cotton bolls 30 

mistaken for boll weevil 30 

A rsenate of lead against boll weevil 150-151 

Aslnnouni. (-See Cotton, Egyptian.) 

Aspergillus, fungous enemy of boll weevil 136 

Bseolophns atricristatus, enemy of boll weevil 146 

bicolor, enemy of boll weevil 146 

Balaninus nasicus attacks acorns 30 

mistaken for boll weevil 30 

victoriensis attacks live oak acorns 30 

attraction to lights 154 

mistaken for boll weevil 30, 154 

Ba pt isia at tacked by Tych ius sordidus 30 

Boris striata attacks roots of ragweed (Ambrosia) 30 

mistaken for boll weevil 30 

transversa attacks roots of cocklebur (Xanthium) 30 

mistaken for boll wevil 30 

28873°— S. Doc. 305, 62-2 12 177 



178 THE MEXICAN COTTON-BOLL WEEVIL. 

Page. 

Bark, hibernation shelter for boll weevil 101 

Bartramia longicauda, enemy of boll -weevil 146 

Bermuda grass, duration of life of boll weevils fed thereon 48 

Bindweed. (See Convolvulus repens.) 

Birds inimical to boll weevil 145-146 

Blackberry, host plant of Anthonomus signatus 30 

Blackbird, Brewer. (See Euphagus cyanocephalus. ) 
red-winged. (See Agelaius pJmniceus.) 
rusty. (See Euphagus carolinus.) 

Bloodweed, duration of life of boll weevils fed thereon 48 

Blue jay. (See Cyanocitla cristata.) 

Boll weevil, abundance, seasonal 74-85 

variations from year to year 83-85 

activity, zone of temperatures causing il 127 

adult, ability to locate cotton 41 

activity after emergence from hibernation 116-118 

attraction to various cottons 45-47 

substances 42-43 

changes after emergence 38 

color 36 

description 35 

of teneral stage 34-35 

destructive power by feeding 42 

duration of life according to sex 50 

average 47-50 

with normal food 49 

without normal food 48-49 

effects upon squares and bolls of feeding 44^5 

emergence 38 

feeding activity 41-A2 

habits of hibernated weevils 41-42 

female, characters 37 

food habits 38-50 

habits, food 38-50 

protective 38 

longevity, maximum 115-116 

of those emerging from hibernation 111-116 

male, characters 37 

movements on food plant 43^44 

number on stalks at different dates 99 

under rubbish 99 

protective habits 38 

secondary sexual characters 37 

sense of color 43 

size 35-36 

weight 36 

aestivation, zone of temperatures causing it 127 

annual movement in square miles 27-28 

bibliography 169-175 

bird enemies 145-146 

breeding habit, the one probably original 62 

broods 74-76 

cannibalism 50 

causes for natural dissemination 87 

checked by altitude 28-29 

dryness 28 

low temperature 28 

climatic control, effect of cold 19 

drought 16 

early frost 20 

influences on vitality and activities 121-122 

compensations for losses caused thereby 26-27 

control by climatic conditions 1 20-132 

parasites 120 

predators 120 

proliferation 132-135 



INDEX. 



179 



Page. 

Boll weevil, copulation, age at beginning 52 

• duration of act "^ 

description - 33-37 

development during winter -lot 

diseases 

dispersion. (-See Boll weevil, dissemination.) 

dissemination annually in square miles 27-^8 

artificial, intentional transportation 94 

movement of baled cotton 93 

cottonseed 92-93 

farm hands 93-94 

seed cotton 91-92 

vehicles 93 

as affected by leaf worm (Alabama argillacea) 87 

natural, causes ( 87 

'fall dispersion 87-90 

hibernation flight 90 

other forms of natural spread 90-91 

spring search for cotton 85-91 

spread withi n the field 86 

summer flights 86-87 

distribution - „?°7^J 

effects "thereon of flooding - -_ l6L idZ 

egg deposition. (See Boll weevil, oviposition.) 

description J™ 

duration of stage - b - ^ 

eggs eaten by adult when laid outside 

hatching - - -. 

of those laid outside of cotton fruit 64 

percentage Jjjj 

fall dispersion ioo i qi 

fatalities from temperature variations ....... L2J-L 31 

lower zone of temperatures causing it 128 

upper zone of temperatures causing it 126 

faunal zone limits 29 

fecundity 60-61 

fertility, duration ^ j*j 

fertilization 5_-o3 

first account of damage }■> 

food habits *b-M 

Plants U-jf 

generations y_ ' " 

hibernation i no 

activity during period - J03 

emergence therefrom 107-110 

activity of adults thereafter. . . 116-118 

longevity thereafter 114-116 

rate 108-110 

time 107-108 

entrance 96-99 

flight 90 

length of period, average 103-105 

extremes of variation 105 

relation of shelter thereto 105-106 

methods of study _ 95-96 

number of adults entering 98-99 

shelter , 100-102 

sources of weevils entering 96 

stages entering 96-97 

survival IjO- 114 

influence of climate thereon 112-114 

fall destruction of cotton stalks 

thereon 111-112 

shelter thereon 112 

time of entrance . . . . 97-98 

zone of temperatures causing it 127-128 



180 THE MEXICAN COTTON-BOLL WEEVIL. 

Page. 

Boll weevil, history 15-20 

in Alabama 20 

Arkansas 20 

Costa Rica 20 

Cuba 16, 19, 21 

Florida 20 

Guatemala 18 

"Laguna " district of Mexico, discovery 18 

Louisiana 20 

Mexico 15,16,19,20 

Mississippi 20 

Oklahoma 20 

Texas 20 

• infestation, maximum, and its effect on multiplication 79-80 

progress, in fields 77-79 

insect control by months 144-145 

highest records 145 

enemies 136-145 

insects mistaken therefor 29-30 

intentional transportation 94 

invasion of Alabama 19 

Arkansas 19 

Florida 20 

Louisiana IS 

Mississippi 19 

Oklahoma 19 

Texas 16 

larva, description 33-34 

duration of stage 66 

food habits 65 

growth 65 

molts 66 

life cycle - 69-74 

average duration 69 

in hanging squares 73 

variations due to location of developing stage 69 

sex 69 

temperature 70-72 

time of falling of infested scpiares 69-70 

in bolls 72 

miscellaneous 72-73 

history, summary 32-33 

losses due thereto 21-26 

compensation therefor 26-27 

indirect, due thereto 26 

mortality by sections 119-120 

due to heat and dryness 122-124 

in all classes of cotton forms 118-120 

natural control 118-146 

effect of defoliation of cotton 20 

origin 15-20 

oviposition, act 56-58 

activity at various times of day 58-59 

age at beginning 53-54 

dependence thereof upon food obtained from squares.. 55-56 

effects upon squares 61-62 

examination of squares before the act 54 

period 61 

place of egg deposition 56 

seasonal rate 59-60 

selection of squares 54-55 

stimulating effect of abundance of squares 58 

time required to deposit an egg 58 

parasite control by years 144 

parasites, rotation of hosts 143 

parthenogenesis 53 



INDEX. 



181 



Page. 

Boll weevil, percentage developed from infested squares - 68 

plant control - - : \H~\ir 

by structural characteristics loo-loo 

possible annual progeny ofloq 

prospects ft 

pupa, activity "7 

description Jg 

duration of stage - 0/ °^ 

pupal cells 67 

pupation - - 6/ 

relation to top crop of cotton 147 irq 

repres5ion a, ^::::::::. ::::::::::::::::::::::::::::' a^-m %&* 

basis 15 n~l?? 

by arsenate of lead 150-151 

burial of squares 147-149 

chain cultivator 151 

destruction of cotton stalks 160 

weevils during winter 160 

early crop of cotton 160-161 

encouraging insect enemies 161 

fumigation of cotton seed 162-163 

hand-picking of weevils and squares 161 

increasing effects of climatic conditions 161 

insecticides 149-151 

legal restrictions 164-168 

machinery ^1453 

quarantine - 160 

stalk destruction 157-158 

futile methods 153-155 

futility of attempting to restrict cotton production 156-157 

castor bean plant 155 

cottonseed oil 153 

mineral paint 153 

Paris green 154 

pepper plants 155 

spraying 153 

sulphur 153 

tobacco 155 

trapping at lights 154 

requirements of satisfactory method 155 

summary of means 160-162 

seasonal abundance . 74-85 

sexes, seasonal proportion. 51-52 

sex of hibernated boll weevils 51-52 

individuals ready to enter hibernation 51 

spring and summer boll weevils 51 

sexual attraction 52 

sporadic occurrences, unexplained 94 

spread. (See Boll weevil, dissemination.) 

spring search for cotton 85-86 

spread within field 86 

status examinations 80-81 

summary of life history 32-33 

repressive measures 160-162 

summer flights 86-87 

temperature relationships 125-131 

variations fatal 129-131 

zones 125-128 

Bollworm. (See Heliothis obsoleta.) 
Bracon mellitor. (See Microbracon mellitor.) 

Bruchophagus herrerse, enemy of boll weevil 141 

Buildings as hibernation shelter for boll weevil 102 

Bunting, painted. (See Passerina ciris.) 

Burial of squares, effect on boll weevil 147-149 



182 THE MEXICAN COTTON-BOLL WEEVIL. 

Page. 
Callirhoe (see also Mallow). 

buds, duration of life of boll weevils fed thereon 48 

involucrata, tested as food plant of boll weevil 32 

Cardinal. (See Cardinalis cardinalis.) 

Cardinalis cardinalis, enemy of boll weevil 146 

Careless weed. (See Euphorbia.) 

Castor bean plants, futility against boll weevil 155 

Cathartus gemellatus, enemy of boll weevil 138 

( 'atolaccus hunteri, enemy of boll weevil 141 

incertus, enemy of boll weevil 141 

Cerambycobius cushmani, enemy of boll weevil 141 

cyan iceps, enemy of boll weevil 141 

sp., enemy of boll weevil 141 

Chain cultivator, use against boll weevil 151 

Chalcodermus xneus attacks cowpea pods 30 

breeds in cotton squares 30 

mistaken for boll weevil 30 

Chat, yellow-breasted. (See Icteria virens.) 

Chauliognathus spp., enemies of boll weevil 137 

Chickadee, Carolina. (See Penthestes carolinensis.) 

China-berries attacked by Arsecerus fasciculatus 30 

Chondestes grammacus, enemy of boll weevil 146 

Chordeiles virginianus, enemy of boll weevil 146 

Climate, factor in boll-weevil control 120-132 

mortality 120-132 

Climatic conditions, factor in boll-weevil control 120-132 

influences on vitality and activities of boll weevil 121-122 

Cocklebur. (See Xanthium.) 

Coffee beans attacked by Arsecerus fasciculatus 30 

bean weevil. (See Arxcerus fasciculatus.) 

Cold, effect on boll weevil L9. 28 

Colinus virginianus, enemy of boll weevil L46 

Colors, attractiveness to boll weevil 43 

Conotrachelus elegans attacks galls and nuts of pecan 30 

mistaken for boll weevil 30 

erinaceus mistaken for boll weevil 30 

leucophseatus attacks stems of careless weed (Euphorbia) 30 

mistaken for boll weevil 30 

naso attacks acorns 30 

mistaken for boll weevil 30 

nenuphar (see also Plum curculio). 

attacks fruit of plums and peaches 30 

mistaken for boll weevil 30 

Convolvulus repens tested as food plant of boll weevil 32 

Cordyceps, fungous enemy of boll weevil 136 

Corn, duration of life of boll weevils fed thereon 48 

Cornstalks, hibernation shelter for boll weevil 101 

Cotton, American Upland, susceptibility to boll-weevil attack 45, 46 

baled, factor in dissemination of boll weevil 93 

bolls, duration of life of boll weevils fed thereon 49 

effect of feeding by boll weevil thereon 45 

old, attacked by Arsecerus fasciculatus 30 

pendent, indirect effect on boll weevil 135 

with thick walls, effect on boll weevil 136 

boll weevil. (See Boll weevil.) 

caterpillar. (See Alabama argillacea and Leaf worm.) 

Cuban, susceptibility to boll-weevil attack 45, 46 

destruction of stalks as a means of boll-weevil repression 157-158 

determinate growth, effect on boll weevil 135 

early bearing, effect on boll weevil 135 

maturing varieties as a means of boll-weevil repression 160-161 

planting as a means of boll-weevil repression 160-161 

Egyptian, susceptibility to boll-weevil attack 45. 46 

fall destruction of stalks in relation to survival of boll weevil from hiber- 
nal ion 111-112 

fertilization as an aid to boll-weevil repression L60-161 

flowers attacked by Echthetopyga gossypii in Philippines 30 



INDEX. 183 

Page. 

Cotton, foliage, duration of life of boll weevils fed thereon 49 

food plant of Alabama argillacea 15 

Anthonomus grandis 1-175 

vestitus 30 

Anthribus cornutus 30 

Chalcodermus seneus 30 

Echthelopyga gossypii 30 

Heliothis obsoleta 15 

hairy stalks, effect on boll weevil 135 

involucral. bracts, effect on boll weevil 136 

"kidney," host plant of boll weevil in Cuba 16, 31 

"loose." (See Gossypium brasiliense.) 

nectar, indirect effect on boll weevil 135 

visited by Gcrseus penicellus 30 

picumnus 30 

picking of squares as a means of boll-weevil repression 161 

planting early as a means of boll-weevil repression * 160-161 

restriction an impracticable means of boll-weevil repression. . 156-157 

time, effect on longevity of boll weevils 116 

plant, proliferation, effect on boll weevil 132-135 

structures inimical to boll weevil 135-136 

retention of fruit, effect on boll weevil 136 

Sea Island, susceptibility to boll-weevil attack 45, 46 

seed, factor in dissemination of boll weevil 92-93 

shallow cultivation as a means of boll-weevil repression 160-161 

squares attacked by Anthonomus vestitus in Peru 30 

Chalcodermus seneus 31 

burial, effect on boll weevil 147-149 

duration of life of boll weevils fed thereon 49 

effect of feeding of boll weevil thereon 44-45 

picking, as a means of boll-weevil repression 161 

square weevil, Peruvian. (See Anthonomus vestitus.) 

stalks as hibernation shelter for boll weevil 100 

destruction in fall as a means of boll-weevil repression 11 1-112 

stems attacked by j 1 nthribus cornutus 30 

top en >p as affected by boll weevil 81-83 

tree, host plant of boll weevil 31 

"wild." (See Gossypium brasiliense.) 

Cottonseed meal, nonattractiveness to boll weevil 42 

oil as bait against boll weevil, futility 153 

Cottonwood catkins attacked by Dorytomus mucidus 30 

Cowbird. (See Molothrus ater.) 

I lowpea curculio (see also Chalcodermus seneus). 

host of Ennyomma globosa 142 

food plant of Chalcodermus seneus 30 

pod weevil. (See Cowpea curculio and Chalcodermus seneus.) 

Cremaslogaster lineolata 1;> viuscula clara, enemy of boll weevil 139 

( 'niton, host plant of Anthonomus albopilosus 30 

Cyanocitta cristata, enemy of boll weevil 146 

Dendroica sest iva, enemy of boll weevil 146 

coronata, enemy of boll weevil 146 

Desmoris constrict us attacks seed of sunflower (Helianthus) 30 

mistaken for boll weevil 30 

scapalis attacks flower heads of broad-leaved gum plant (Sideranthus) . . 30 

mistaken for boll weevil 30 

Dewberry, host plant of Anthonomus signatus 30 

Dickcissel. (See Spiza americana.) 

Dorymyrmex pyramicus. enemy of boll weevil 140 

flavus, enemy of boll weevil 140 

Dorytomus mucidus attacks Cottonwood catkins 30 

mistaken for boll weevil 30 

Drought, effect on boll weevil 16 

Dryness, effect on boll weevil 28 

factor in boll-weevil mortality 122-124 

Eciton ( Acamatus \ commutatus, enemy of boll weevil 139 

Ectatom ma tuberculatum, enemy of boll weevil 139 

Ecthetopyga gossypii feeds in cotton flowers in Philippines 30 



184 THE MEXICAN COTTON-BOLL WEEVIL. 



Empidonax minimus, enemy of boll weevil 146 

trailli alnorum, enemy of boll weevil 146 

Ennyomma globosa. enemy of boll weevil 142 

cowpea curculio ( Chalcodermus seneus) 142 

Epicserus imbricatus mistaken for boll weevil 30 

Euphagus carolinus, enemy of boll weevil 146 

cyanocephalus, enemy of boll weevil 146 

Euphorbia stems attacked by Conotrachelus leucophseatus 30 

Eurytoma sp. , enemy of boll weevil 141 

tylodermatis, artificial increase of effectiveness as boll-weevil parasite. 143 

enemy of boll weevil 141 

Evarthrus sodalis, enemy of boll weevil 137 

sp., enemy of boll weevil ' 137 

Excelsior, duration of life of hibernated boll weevils fed thereon 48 

False indigo. (See Baptisia.) 

Farm hands, movement, factors in dissemination of boll weevil 93-94 

Faunal zone limitations upon boll weevil 29 

Flooding, effects upon boll weevil 131-132 

Flycatcher, alder. (See Empidonax trailli alnorum.) 
crested. (See Myiarchus crinitus.) 
least. (See Empidonax minimus.) 
olive-sided. (See Nuttallornis borealis.) 
scissor-tailed. (See Muscivora forficata.) 

Forelius maccooki, enemy of boll weevil 140 

Formica pallidifulva, enemy of boll weevil 140 

subpolita perpilosa, enemy of boll weevil 140 

Geothlypis trichas, enemy of boll weevil 146 

Gerseus penicellus mistaken for boll weevil 30 

visits cotton nectar 30 

picumnus mistaken for boll weevil 30 

visits cotton nectar 30 

Gerstseclceria nobilis attacks joints of prickly pear 30 

mistaken for boll weevil 30 

Ginning machinery used in repression of boll weevil 152-153 

Gossypium (see also Cotton). 

brasiliense, food plant of boll weevil 16, 31 

Grackle, bronzed. (See Quiscalus q. seneus.) 

great-tailed. (See Megaquiscalus major macrourus .) 
Guatemalan ant. (See Ectatomma tuberculatum.) 
Gum plant, broad-leaved. (See Sideranthus.) 

Habrocytus piercei, enemy of boll weevil 141 

Hay, duration of life of boll weevils fed thereon 48 

Heat, factor in boll-weevil mortality 122-1 24 

Helianthus (see also Sunflower). 

annuus, tested as food plant of boll weevil 32 

seed attacked by Desmoris constrictus 30 

Heliothis obsoleta an enemy of cotton 15 

Hibiscus africanus, buds, duration of life of boll weevils fed thereon 48 

tested as food plant of boll weevil 31, 32 

buds, Japanese, duration of life of boll weevils fed thereon 48 

esculentus tested as food plant of boll weevil 31 

leaf, duration of life of boll weevils fed theVeon 48 

manihot tested as food plant of boll weevil 31 

militaris, buds, duration of life of boll weevils fed thereon 48 

tested as food plant of boll weevil 31, 32 

moscheutos, buds, duration of life of boll weevils fed thereon 48 

tested as food plant of boll weevil 31,32 

vesicarius tested as food plant of boll weevil 31, 32 

Hirundo erythrogastra, enemy of boll weevil 146 

Hollyhock (see also Althaea sp.). 

buds, duration of life of boll weevils fed thereon 48 

Honey, attractiveness to boll weevil 43 

Hydnocera pallipennis, enemy of boll weevil 138 

pubescens, enemy of boll weevil 138 

Hylobius pales attacks pine bark 30 

mistaken for boll weevil 30 



INDEX. 185 

Page. 

Icteria wrens, enemy of boll weevil 146 

Icterus bullocki, enemy of boll weevil 146 

galbula, enemy of boll weevil 146 

hypomelas, enemy of boll weevil in Cuba 145 

spurius, enemy of boll weevil 146 

Indigo, false. (See Baptisia. ) 

Insect enemies of boll weevil 136-145 

Insecticides used against boll weevil 149 1 5 1 

Iridomyrmex analis, enemy of boll weevil 140 

prey of Irid&myrmex humilis 140 

humilis enemy of boll weevil 140 

Iridomyrmex analis 140 

Monomorium pharaonis Ill) 

Solenopsis gem inula 140 

Janovitch. (See Cotton, Egyptian.) 
' ' Kelep . ' ' (See Ectatomma t u bercu latum. . ) 
Killdeer. (See Oxyechus vociferus.) 
Kingbird. (See Tyrannus tyrannus.) 

Luii ins ludovicianus, enemy of boll weevil 146 

Lariophagus texanus, enemy of boll weevil 142 

Leaf worm (see also Alabama argillacea). 

effect of defoliation on boll weevil 20 

Live oak acorns attacked by Btilan in us victoriensis 30 

lAxus scrobicollis attacks stems of ragweed (Ambrosia) 30 

mistaken for boll weevil 30 

Machinery used against boll weevil 151-153 

Macrocheles n . sp. , enemy of boll weevil 137 

Mallow, purple, host plant of Anthonomus /ulcus 30 

trailing. (See Callirhoe.) 
Martin, purple. (See Progne subis.) 
Meadowlark. (See Sturnella magna.) 

western. (See Sturnella neglecta.) 

Megaqulwalus major maerourus, enemy of boll weevil 146 

Melospiza georgiana, enemy of boll weevil 14(i 

Mtcrobracon mellitor, enemy of boll weevil 142 

Microdontomerus anthonomi, enemy of boll weevil 141 

Mi nuts poly gl ottos, enemy of boll weevil 146 

Mineral paint, futility against boll weevil 153 

M it afifi. (See Cotton, Egyptian.) 
Mockingbird. (See Mimus polyglottos.) 

Molasses, nonattractiveness to boll weevil 43 

Mulothrus ater, enemy of boll weevil 146 

Monomorium minimum , enemy of boll weevil 140 

pharaonis, enemy of boll weevil 140 

prey of Iridomyrmex hum His 140 

Morning glory pods attacked by Rhyssematus palmacollis 30 

Muscivora forficata, enemy of boll weevil 146 

Myiarchus crinitus, enemy of boll weevil 146 

Myiophasia a nea, enemy of boll weevil 142 

Nannus hyemalis, enemy of boll weevil 146 

Nighthawk. (See Chordeiles virginianus.) 

\ uttallornis borealis, enemy of boll weevil 146 

< tats, duration of life of boll weevils fed thereon 48 

Okra buds, duration of life of boll weevils fed thereon 48 

leaf, duration of life of boll weevils fed thereon 48 

tested as food plant of boll weevil 32 

Opatrin us notus, enemy of boll weevil 138 

Oriole, Baltimore. (See Icterus galbula.) 
Bullock. (See Icterus bullocki.) 
Cuban. (See Icterus hypomelas.) 
orchard. (See Icterus spurius. I 

< > i i/i <li us voci/erus, enemy of boll weevil 146 

Pachylobius pici varus attacks pine branches and bark 30 

mistaken for boll weevil 30 

Parasites, factor in control of boll weevil 120 

Paris green, futilitv against boll weevil 154 



186 THE MEXICAN COTTON-BOLL WEEVIL. 

Page. 

Passerculus sandwichensis, enemy of boll weevil 146 

Passer* lla iliaea, enemy of boll weevil. .: 146 

Passerina ciris, enemy of boll weevil 146 

Peaches attacked by Conotrachelus nenuphar 30 

Pecan galls and nuts attacked by Conotrachelus elegans 30 

Pediculoides vp. , enemy of boll weevil 137 

ventricosus, enemy of boll weevil 137 

Penthestes carolinensis, enemy of boll weevil 146 

Pepper, host plant of Anthonomus eugenii 30 

plants, futility against boll weevil 155 

Perilampus sp., enemy of boll weevil 141 

Petrochelidon lunifrons, enemy of boll weevil 146 

Pheidole crassicorn is, enemy of boll weevil 140 

sp., near flavens, enemy of boll weevil 140 

Phoebe. (See Sayornis phce.be.) 
Pigweed (see also Amaranthus spp.). 

duration of life of boll weevils fed thereon 48 

Pimpla sp. , enemy of boll weevil 142 

Pine bark attacked by Hylobius pales 30 

branches and bark attacked by Pachylobius picivorus 30 

Pissodes nemorensis 30 

I'ipiJo erythrophthalmus, enemy of boll weevil 146 

Pipit, American. (See Anthus pe7isilvanicus .) 

Pissodes nemorensis, attacks pine branches and bark 30 

mistaken for boll weevil 30 

Plant control of boll weevil. 132-136 

Plover, upland. (See Bartramia longicauda.) 
Plum curculio (see also Conotrachelus nenuphar). 

host of Sigalphus curculionis 142 

Plums attacked by Conotrachelus nenuphar 30 

Pocecetes gramineus, enemy of boll weevil 146 

Precipitation, effect on date of beginning emergence from hibernation by boll 

weevil. 107-108 

survival of hibernating boll weevils 112-114 

Predators, factor in control of boll weevil 120 

Prenolepis imparls, enemy of boll weevil 140 

Prickly pear attacked by Gerstseckeria nobilis 30 

Progne subis, enemy of boll weevil 146 

Proliferation, control of boll weevil thereby 132-135 

Pyrrhuloxia s. texana, enemy of boll weevil 146 

Texan. (See Pyrrhuloxia s. texana.) 
Quail. (See Colinus virginianus .) 

Quarantine against boll weevil by Alabama 165 

California 165 

Egypt 168 

Florida 165 

Georgia 165-166 

India. 1 68 

Louisiana 166 

Mississippi 166 

North Carolina 166-167 

Oklahoma 167 

Peru 1 68 

Porto Rico 167 

South Carolina 167-168 

Tennessee 168 

Texas 168 

Quiscalus q. seneus, enemy of boll weevil 146 

Ragweed. (See Ambrosia.) 
Rainfall. (See Precipitation.) 

Rains as agents in spread of boll weevil 91 

Real rift ion of cotton planting now an impract icable means of boll weevil repres- 
sion 156-157 

Rhynch ites mexicanus attacks rosebuds 30 

no istaken for boll weevil 30 

Rhyssematus palmacollis attacks morning glory pods 30 

mistaken for boll weevil 30 



INDEX. 187 

Page. 

Rice, duration of life of hibernated boll weevils fed thereon 48 

Riparia riparia, enemy of boll weevil 1 Hi 

Rosebuds attacked by Rhynchites mexicanus 30 

Sage, wild. (See Croton.) 

Sayornis phcebe, enemy of boll weevil 1 Hi 

Seed cotton, factor in dissemination of boll weevil 91-92 

Shrike, loggerhead. (See Lanius ludovicianus .) 

Sideranthus attacked by Desmoris scapalis 30 

Sigalphus curculionis, enemy of boll weevil I I :' 

plum curculio (Conotrachelus nenuphar) I 12 

Solanum rostratum stalks attacked by Tnchobaris texana 30 

Solenopsis geminata diabola, enemy of boll weevil L39 140 

prey of Iridomyrmex humilis I 10 

molesta, enemy of boll weevil I 10 

texana, enemy of boll weevil I 10 

Sorghum cane, duration of life of boll weevils fed thereon 48 

Spanish moss as hibernal ion shelter for boll weevil 101 

th istle. (See Solanum rostratum . ) 
Sparrow, field. | See Spizella pusilla .) 
l'( ix . (See Passerella iliaca. ) 
lark. (See Chondestes grammacus.) 
savanna. (See Passerculus sandwichensis, ) 
swamp. (See Melospiza georgiana.) 
vesper. (See Pocecetes gramineus. ) 
white-throated. (See Zonotrichia albicollis. ) 

Spilochalcis sp., enemy of boll weevil Ill 

Spiza anu Tirana, enemy of boll weevil I 46 

Spizella pusilla, enemy of boll weevil I Mi 

Spraying, futility against boll weevil 153 

Stagmomantis limbata, enemy of boll weevil 137 

Stalk-cutting device for cotton 158 

Strawberry, host plant of Anihonomus signatus 30 

Sturnella magna, enemy of boll weevil .- 14G 

neglecta, enemy of boll weevil 140 

Sugar, nonattractiveness to boll weevil 43 

Sulphur, futility against boll weevil 153 

Sunflower (see also Helianthus). 

duration of life of boll weevils fed thereon 48 

Swallow, bank. (See Riparia riparia.) 

barn. (See Hirundo erythrogastra.) 
cliff. (See Petrochelidon lunijrons.) 
Temperature, effect upon date of beginning emergence from hibernation by 

boll weevil. 107-108 

entering hibernation 97-98 

duration of egg stage of boll weevil 62-63 

larval stage of boll weevil 66 

pupal stage of boll weevil 67-68 

life cycle of boll weevil 70-72 

locomotion of boll wevil 43-44 

oviposition of boll weevil 58-59 

survival of hibernating boll weevils 112-114 

fatal variations for boll weevil 129-131 

relations to boll weevil 125-131 

zone of activity for boll weevil 127 

fatality, lower, for boll weevil 128-131 

upper, for boll weevil L26 

hibernation for boll weevil 127-128 

TV trastichus h unteri, enemy of 1 >< ill weevil 142 

Thistle, Spanish. (See Spanish thistle.) 
Thrasher, brown. (See Toxostoma rufum.) 

Thryomanes bewicM, enemy of boll weevil 146 

Thryothorus ludovicianus, enemy of boll weevil L46 

Tie vine, duration of life of boll weevils fed thereon 

Tillandsta usneoides. (See Spanish moss.) 
Titmouse, black-crested. (See Bicolophus atricristatus.) 
tufted. (See Bseolophus hicolor.) 



188 THE MEXICAN COTTON-BOLL WEEVIL. 

Page. 

Tobacco, futility against boll weevil 155 

stalks attacked by Trichobaris m ucorea 30 

Towhee. (See Pipilo erythrophthalmus.) 

Toxostoma rufum, enemy of boll weevil 146 

Trapping at lights, futility against boll weevil 154 

Trichobaris mucorea attacks tobacco stalks 30 

mistaken for boll weevil 30 

texana attacks Spanish thistle stalks (Solarium rostratum) 30 

mistaken for boll weevil 30 

Tychius sordidus attacks pods of false indigo (Baptisia) 30 

mistaken for boll weevil 30 

Tyrannus tyrannus, enemy of boll weevil 146 

Tyroglyphus breviceps, enemy of boll weevil 137 

United States statute regarding boll weevil 164 

Urosigalphus anthonomi, enemy of boll weevil 142 

schwarzi, enemy of boll weevil 142 

sp., enemy of boll weevil 142 

Vehicles, factors in dissemination of boll weevil 93 

Warbler, myrtle. (See Dendroica coronata.) 
yellow. (See Dendroica xstiva.) 

Water, duration of life of boll weevils fed thereon 48 

hibernated boll weevils fed thereon 48 

Windstorms as agents in spread of boll weevil 90 

Wren, Bewick. (See Thryomanes bewicki.) 

Carolina. (See Thryothorus ludovieianus .) 
winter. (See Nannus hyemalis.) 

Xanthium roots attacked by Baris transversa 30 

Yellowthroat, Maryland. (See Geothlypis trichas.) 

Zonotrichia albicollis, enemy of boll weevil 146 

o 









U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 115. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PAPERS ON DECIDUOUS FRUIT INSECTS 
AND INSECTICIDES. 



CONTENTS AND INDEX. 



Issued Pebruary 5, 1915. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1816. 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 115. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PAPERS ON DECIDUOUS FRUIT INSECTS 
AND INSECTICIDES. 



I. LIFE-HISTORY STUDIES ON THE CODLING MOTH IN MICHIGAN. 

By A. Q. HAMMAR, Entomological Assistant, 
Deciduous Fruit Insect Investigations. 

IV THE ONE-SPRAY METHOD IN THE CONTROL OF THE CODLING MOTH 
AND THE PLUM CURCULIO. (SECOND REPORT.) 

By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations, 



E. W. SCOTT, Entomological Assistant. 

III.ILIFEI.HISTORY OF THE CODLING MOTH IN THE SANTA CLARA 
VALLEY OF CALIFORNIA. 

By P. R. JONES and W. M. DAVIDSON, 
Entomological Assistants, Deciduous Fruit Insect Investigations. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1915. 



B UREAU OF ENTOMOLOGY. 

L. 0. Howard, Entomologist and Chief of Bureau. 
C. I>. Marlatt, Entomologist and Acting Chief in Absence of Chief. 
R. S. Clifton, Chief Clerk and Executive Assistant. 
F. H. Chittenden, in charge of truck crop and stored product insect investigations. 
A. D. Hopkins, in charge of forest insect investigations. 
W. D. Hunter, in charge of southern field crop insect investigations. 
F. M. Webster, in charge of cereal and forage insect investigations. 
A. L. Quaintance, in charge of deciduous fruit insect investigations. 
E. F. Phillips, in charge of bee culture. 

A. F. Burgess, in charge of gipsy moth and brown-tail moth investigations. 
Rolla P. Currie, in charge of editorial work. 
Mabel Colcord, in charge of library. 

Deciduous Fruit Insect Investigations. 

A. L. Quaintance, in charge. % 

Fred E. Brooks, John B. Gill, R. L. Nougaret, A. C. Baker, R. A. Cushman, 
J. F. Strauss, W. F. Turner, J. H. Paine, E. H. Siegler, W. B. Wood, F. L. 
Soianton, E. B. Blakeslee, H. B. Scammell, entomological assistants. 

E. J. Newcomer, W. M. Davidson, A. J. Ackerman, R. J. Fiske, Dwight Iselt, 
E. W. Geyer, A. I. Fabis, B. R. Leach, H. G. Ingerson, H. K. Plank, scien- 
tific assistants. 

E. W. Scott, W. S. Abbott, J. E. Dudley, Jr., employed in enforcement of insecticide 
act of 1910. 

v 



CONTENTS. 

Page. 

Life-History Studies on the Codling Moth in Michigan. A. (J. Hammar. . 1 

Introduction 1 

Definition of terms used 2 

Seasonal-history studies of 1909 3 

Time of emergence of moths of spring brood 3 

Time of emergence of moths of the first brood 4 

Baud -record experiments in 1909 5 

Seasonal-history studies of 1910 6 

Wintering larvae 6 

Spring brood of pupae 8 

Spring brood of moths 11 

The first generation 14 

The second generation 23 

Band records of 1910 26 

Summary of seasonal-history studies of 1910 31 

Seasonal-history studies of 191 1 32 

Source of rearing material 33 

Winter-killed larvae 33 

Spring brood of pupae 34 

Spring brood of moths 37 

The first generation 42 

The second generation 55 

Band records of 1911 60 

Summary of seasonal-history studies of 1911 65 

Weather records for 1909, 1910, and 1911 66 

Comparative life-history studies for the seasons of 1909. 1910. and 191 1 . . . . 70 

Insect enemies ". 73 

Predaceous insects 73 

Parasitic insects 74 

Nematode worms 76 

Miscellaneous observations 76 

Number of larval instars and molts of the codling moth 76 

Cannibalism among larvae of the codling moth 83 

Codling moth larvae remaining two seasons in the larval stage 83 

Codling moth larvae feeding on apple foliage 84 

Summary 84 

The One-Spray Method in the Control of the Codling Morn and the 

Plum Curculio (second report). A. L. Quaintance <in<l /•.'. IT. Scott.. 87 

1 ntroduction 87 

Experiments in Virginia 88 

The codling moth 89 

The plum curculio , 91 

VII 



VIII DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

The One-Spray Method in the Control of the Codling Moth and the 

Plum Curculio (second report) — Continued. Page. 

Experiments in Michigan 92 

The codling moth 94 

Experiments in Delaware 98 

The codling moth 100 

The plum curculio 102 

Experiments in Kansas 102 

The codling moth 105 

Summary of results 107 

Conclusions 110 

Life History of the Codling Moth in the Santa Clara Valley of Cali- 
fornia P'. R. Jones and W. M. Davidson. . 113 

Introduction 113 

Seasonal-history studies of 1909 114 

Spring brood of pupae 114 

Spring brood of moths 115 

First generation 115 

Second generation 118 

Seasonal-history studies of 1910 119 

Spring brood of pupae 119 

Spring brood of moths 122 

First generation 126 

Second generation 135 

Review of life-history work of 1910 142 

Seasonal-history studies for 1911 143 

Spring brood of pupae 143 

Spring brood of moths 147 

First generation ! 150 

Second generation 156 

Natural enemies of the codling moth 160 

Parasitic insects 160 

Predaceous insects 161 

Band records of 1909 161 

Band records of 1910 162 

Band records of 1911 163 

First-brood emergence v. overwintering emergence, 1911 164 

Review of life-history work of 1911 165 

Comparison of life history in 1910 and 1911 165 

Weather records for 1909, 1910, and 1911 166 

Comparative life-history studies for the seasons 1909, 191 0, and 1911 170 

Control of the codling moth on pears and apples in the Santa Clara Valley. 171 

The O'Toole pear orchard at Alviso, Cal 172 

Spraying operations 172 

Season of 1910 172 

Season of 1911 175 

The Northern apple orchard 177 

Season of 1911 177 

Conclusions from experiments in control 179 

Summary 180 

Index 183 



ILLUSTRATIONS 



PLATES. 



Page. 

Plate I. The codling moth (Carpocapsa pomonella). Fig. 1. -Variation in size 
of moths of the spring brood. Fig. 2. — Two moths resting on the 
trunk of an apple tree, showing protective coloration. Fig. 3. — 
Larva in winter cocoon. Fig. 4. — Larva in the act of remodeling 
the winter cocoon. Fig. 5. — Modified winter cocoon, with exit 
tube and silk partition. Fig. 6. — Cocoon after emergence of moth. 

Fig. 7. — Variation in size of wintering larvae 1 

II. Outdoor shelter used in rearing the codLng moth in 1910 and 1911 at 

Douglas. Mich 6 

III. Insect enemies of the codling moth. Fig. 1. — Ascogaslcr carpocapsss, 

a hymenopterous parasite of codling-n >th larvae. Fig. 2. — Cocoon 
of Ascogaster carpocapsse within a cocoon of the codling moth. 
Fig. 3. — Pinacodera limbata, a predaceous beetle destructive to cod- 
ling-moth larvae. Figs. 4, 5. — Tenebroides corticalis, beetle and 
larva, which feed upon the larva and pupa of the codling moth 74 

IV. Fig. 1. — Picked apples from three trees of Plat I (demonstration) in 

the Edward Hutchins orchard, Fennville, Mich. Fig. 2. — Picked 
apples from three trees of Plat III (one spray) in the Edward 
Hutchings orchard, Fennville, Mich. Fig. 3. — Picked apples from 
three trees of Plat V (unsprayed) in the Edward Hutchins orchard, 
Fennville, Mich 96 

TEXT FIGURES. 

Fig. 1. Emergence curve of spring brood of moths in 1909 at Douglas, Mich. 

Records of R. W. Braucher 3 

2. Emergence curve of first brood of moths in 1909 at Douglas, Mich . , 4 

3. Curves showing maturity of larva? of first and second broods; band- 

record curve of 1909 at Douglas, Mich 5 

4. Device in obtaining pupal records of the codling moth 8 

5. Diagram showing time of spring pupation of codling moth in 1910 at 

Douglas, Mich 9 

6. Emergence curve of spring brood of moths in 1910 at Douglas, Mich 12 

7. Emergence curve of summer brood of moths in 1910 at? Douglas, Mich . . 18 

8. Cage used in determining feeding period of codling-moth larva? 26 

9. Burlap bands on apple tree to catch codling-moth larvae 28 

10. Curves made from band-record experiments in orchards at the lake 

shore near Douglas, at Saugatuck, and at New Richmond, Mich., 

1910 30 

11. Diagram to illustrate seasonal history of the codling moth as observed 

during 1910 at Douglas, Mich 32 

12. Curve of spring pupation of the codling moth in 1911 at Douglas, Mich. . 35 

13. Curve showing relation of temperature to the duration of the pupal 

stage in the spring brood of the codling moth ; Douglas, Mich., 1911 . . 36 

IX 



X DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

Page. 
Fig. 14. Emergence curve of moths of the spring brood in 1911 at Douglas, 

Mich 38 

15. Curve showing relation of the temperature to the time of incubation of 

first-brood and second-brood eggs of the codling moth at Douglas, 
Mich., 1911 45 

16. Emergence curve of moths of the summer brood in 1911 at Douglas, 

Mich 50 

17. Mailing case used for shipping codling-moth larvae 62 

18. Curves made from band-record experiments in orchards at the lake 

shore near Douglas, at Douglas, and at New Richmond, Mich., 1911 . . 64 

19. Curves made from band-record experiments in orchards at Pentwater, 

Douglas, and Benton Harbor, Mich., 1911 66 

20. Diagram illustrating seasonal history of the codling moth as observed 

during 191 1 at Douglas, Mich 67 

21. Diagram showing time of emergence and relative abundance of spring- 

brood and summer-brood codling moths, and blooming period of 
apple trees, during 1909, 1910, and 1911, at Douglas, Mich 71 

22. Diagram showing time of leaving the fruit by the first-brood and 

second-brood larvae of the codling moth during 1909, 1910, and 1911, 

at Douglas, Mich 72 

23. Diagram showing arrangement of plats and trees in the W. F. Gilkeson 

orchard , near Fishersville, Va 88 

24. Diagram showing arrangement of plats and trees in the Edward Hutch- 

ins orchard near Fennville, Mich 93 

25. Diagram showing arrangement of plats and trees in the F. C. Bancroft 

orchard, near Camden, Del 99 

26. Diagram showing arrangement of plats and trees in the Thomas fruit 

farm orchard, near Wichita, Kans 103 

27. Diagram showing emergence of moths, derived from band-record 

material collected in 1909 117 

28. Diagram showing emergence of moths, derived from band-record 

material collected in 1909 118 

29. Diagram showing time of pupation of spring brood of pupae, 1910 . . 119 

30. Diagram showing emergence of first-brood moths for 1910 133 

31. Diagram showing seasonal history of the codling moth during the season 

of 1910 142 

32. Diagram showing pupation of spring brood of larvae, 1911 144 

33. Diagram showing emergence of moths; overwintering brood of 1911 .... 144 
34. ..Diagram showing first-brood pupae, 1911 152 

35. Diagram showing emergence of first-brood moths, 1911 , 154 

36. Diagram showing baud record of 1909 162 

37. Diagram showing band record of 1910 1 63 

38. Diagram showing band record, Northern orchard, 1911 164 

39. Diagram showing seasonal history of the codling moth during the 

season of 191 1 166 



ERRATA. 



Page 1, after Assistant, replace period by comma. 
Page 3, legend to figure 1, for Emergency read Emergence. 
Page 32, legend to figure 1, after Douglas insert a comma. 
Page 42, legend to Table XLII, for emale read female. 
Page L61, line 20, for Melachius read Malachius. 






U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 115, Part I. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PAPERS ON DECIDUOUS FRUIT INSECTS 
AND INSECTICIDES. 



LIFE-HISTORY STUDIES ON THE 

CODLING MOTH IN 

MICHIGAN. 



A. G. HAMMER, 

Entomological Assistant, Deeuktous Fruit Insect 
Investigations. 



Issued August 0, 1012. 





CfcfK&U* 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 115, Part I. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PAPERS ON DECIDUOUS FRUIT INSECTS 
AND INSECTICIDES. 



LIFE-HISTORY STUDIES ON THE 

CODLING MOTH IN 

MICHIGAN. 



A. (J. HAMMAK, 

Entomological Assistant, Deciduous Fruit Insect 
Investigations. 



Issued August it, 1912. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



BUREAU OF ENTOMOLOGY. 

L. 0. Howard, Entomologist and Chief of Bureau. 

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. 

R. S. Clifton, Executive Assistant. 

W. F. Tastst, Chief Clerk. 

F. H. Chittenden, in charge of truck crop and stored product insect investigations. 

A. D. Hopkins, in charge of forest insect investigations. 

W. D. Hunter, in charge of southern field crop insect investigations. 

F. M. Webster, in charge of cereal and forage insect investigations. 

A. L. Quaintance, in charge of deciduous fruit insect investigations. 

E. F. Phillips, in charge of bee culture. 

D. M. Rogers, in charge of preventing spread of moths, field work. 

Rolla P. Currie, in charge of editorial work. 

Mabel Colcord, in charge of library. 

Deciduous Fruit Insect Investigations. 

A. L. Quaintance, in charge. 

Fred Johnson, S. W. Foster, P. R. Jones, F. E. Brooks, A. G. Hammar, E. W. 
Scott, R. L. Nougaret, R. A. Cushman, L. L. Scott, J. B. Gill, A. C. Baker, 
\Y. M. Davidson, E. B. Blakeslee, W. B. Wood, E. H. Siegler, F. L. Simanton, 

entomological assistants. 
J. F. Zimmer, N. S. Abbott, W. II. Sill, entomological assistants, employed in enforce- 
ment of insecticide act, Id 10. 
J . 



CONTENTS 

Page. 

Introduction I 

Definition of tonus used 2 

Seasonal-history studies of 1909 3 

Time of emergence of moths of the spring 1 rood 3 

Time of emergence of moths of the first brood 4 

Band-record experiments in J 909 5 

Seasonal-history studies of 1910 (i 

Wintering larvae G 

The cocoon of the wintering larva (5 

Variation in size of wintering larvae 7 

Winter-killed larva? 7 

Spring hrood of pupa? 8 

Methods of recording pupation 8 

Time of pupation 9 

Length of spring pupal stage 10 

Spring 1 irood of moths II 

Time of emergence II 

Variation in size of moths of the spring brood 11 

Time of oviposition 12 

Length of life of moths L3 

The first generation II 

First brood of eggs It 

Length of incul >ation II 

First brood of larvae 14 

Time of hatching 14 

Length of feeding 15 

Time of maturity of larva* 15 

Percentages of transforming and wintering larvae 15 

Larval life in the cocoon 15 

First brood of pupa; or summer pupae 17 

Time of pupation 17 

Length of pupal stage 17 

First brood of moths or summer moths 18 

Time of emergence 18 

Time of oviposition 19 

Egg deposition by individual moths 29 

Length of life of moths 20 

Life cycle of the first generation 21 

The second generation 23 

Second brood of eggs 23 

Length of incubation 23 

Second brood of larva? 24 

Time of hatching 24 

Length of feeding period 25 

Time of leaving the fruit , 25 

Band records of 1910 26 

Summary of seasonal-history studies of 1910 31 

in 



IV DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

Page. 

Seasonal-history studies of 1911 32 

Source of rearing material 33 

Winter-killed larva? 33 

Spring brood of pupa? 34 

Time of pupation 34 

Length < >f pupal stage 35 

Relation of temperature to the duration of the pupal stage 35 

Spring. brood of moths 37 

Time of emergence of moths 37 

Egg deposition by individual moths 38 

Egg deposition in stock-jar experiments 40 

Period of egg deposition 41 

Length of life of moths 41 

The first generation 42 

First brood of eggs 42 

Length of incubation 42 

Effect of temperature upon time of incubation 44 

First brood of larva? 46 

Time of hatching 46 

Length of feeding period of transforming larvae 46 

Length of feeding period of wintering larvae 46 

Time of maturity of larvae 47 

Percentage of transforming and wintering larva? 47 

1 ,ar val life in the cocoon 47 

First brood of pupa? or summer pupa 1 18 

Time of pupation 48 

Length of pupal stage 49 

First brood of moths or summer mot lis 50 

Time of emergence 50 

Time of oviposition 51 

Length of life of male and female moths 52 

Length of life cycle of the first generation 53 

The second generation 55 

Second brood of eggs 55 

Time of incubation 55 

Effect of temperature upon the time of incubation 58 

Second brood of larva? 58 

Time of hatching 58 

Length of feeding period 60 

Time of maturity (iO 

Band records of 1911 60 

Summary of seasonal-history studies of 191 1 65 

Weather records for 1909, 1910, and 1911 66 

Comparative life-history studies for the seasons of 1909, 1910, and 1911 70 

Insect enemies 73 

Predaceous insects 73 

Parasitic insects 74 

Nematode worms 76 

Miscellaneous observations 76 

Number of larval instars and molts of the codling moth 76 

Cannibalism among larvae of the codling moth 83 

Codling moth Larvae remaining two seasons in the larval stage 83 

( lodling moth larvae feeding on apple foliage 84 

Summary 84 



ILLUSTRATIONS. 



PLATES. 

Page. 

Plate I. The codling moth (Carpocapsa pomonella). Fig. 1. — Variation in size 
of moths of the spring brood. Fig. 2. — Two mollis resting on the 
trunk of an apple tree, showing protective coloration. Fig. 3. — 
Larva in winter cocoon. Fig. 4. — Larva in the act of remodelling 
the winter cocoon. Fig. 5. — Modified winter cocoon, with exit tube 
and silk partition. Fig. 6. — Cocoon after emergence of moth. Fig. 

7. — Variation in size of wintering larvae 1 

IT. Outdoor shelter used in rearing the codling moth in HMO and 1911 at 

Douglas, Mich 

III. Insect enemies of the codling moth. Fig. 1. — Ascogaster carpocapsse, 
a hymenopterous parasite of codling-moth larva*. Fig. 2. — Cocoon 
of Ascogaster carpocapsse within a cocoon of the codling moth. Fig. 
3. — Pinacodera limbata, a predaceous beetle destructive to codling- 
moth larva?. Figs. 4, 5. — Tenebroides cortical is, beetle and larva, 
which feed upon the larva and pupa of the codling moth 74 

TEXT FIGURES. 

Fig. 1. Emergence curve of spring brood of moths in 1909 at Douglas, Mich. 

Records of R. W. Braucher 3 

2. Emergence curve of first-brood moths in 1909 at Douglas, Mich 4 

3. Curves showing maturity of larva? of first and second broods; band- 

record curves of 1909 at Douglas, Mich 5 

4. Device used in obtaining pupal records of the codling moth 8 

5. Diagram showing time of spring pupation of the codling moth in 1910 at 

Douglas, Mich 9 

6. Emergence curve of spring br 1 of moths in 1910 at Douglas, Mich... 12 

7. Emergence curve of summer brood of moths in 1910 at Douglas, Mich.. IS 

8. Cage used in determining feeding period of codling-moth larvae 20 

9. Burlap bands on an apple tree to catch codling-moth larvae 28 

10. Curves made from band-record experiments in orchards at the lake 

shore near Douglas, at Saugatuck, and at New Richmond, Mich., 1910. 30 

11. Diagram to illustrate seasonal history of the codling moth as observed 

during 1910 at Douglas, Mich 32 

12. Curve of spring pupation of the codling moth in 1911 at Douglas, Mich. 35 

13. Curve showing relation of temperature to the duration of the pupal stage 

in the spring brood of the codling moth; Douglas, Mich., 1911 36 

14. Emergence curve of moths of the spring brood in 1911 at Douglas, Mich. 38 

15. Curve showing relation of the temperature to the time of incubation of 

first-brood and second-brood eggs of the codling moth at Douglas, 
Mich., 1911 45 

16. Emergence curve of moths of the summer brood in I'll I at Douglas, 

Mich 50 

17. Mailing case used for shipping codling-moth larvae 02 

v 



VI DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

Page. 
Fig. 18. Curves made from band-record experiments in orchards at the lake 

shore near Douglas, at Douglas, and at New Richmond, Mich., 1911. 64 

19. Curves made from band-record experiments in orchards at Pentwater, 

Douglas, and Benton Harbor, Mich., 1911 66 

20. Diagram illustrating seasonal history of the codling moth as observed 

during 1911 at Douglas, Mich 67 

21. Diagram showing time of emergence and relative abundance of spring- 

brood and summer-brood codling moths, and blooming period of 
apple trees, during 1909, 1910, and 1911 at Douglas, Mich 71 

22. Diagram showing time of leaving the fruit by the first-brood and second- 

brood larvae of the codling moth during 1909, 1910, and 1911 at 
Douglas, Mich 72 



Bui. 1 15, Part I, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate I. 




The Codling Moth (Carpocapsa pomonella). 

Fig. 1. — Variation in size of moths of the spring brood, twice enlarged. Fig. 2. — Two moths 
resting on the trunk of anapple tree, showing protective coloration; enlarged four times. 
Fig. 3. — Larva in winter cocoon. Fig. 4. — Larva in the act of remodeling the winter 
cocoon. Fig. 5. — Modified winter cocoon, with exit tube and silk partition. Fig. 6. — 
Cocoon after emergence of moth, enlarged. Fig. 7. — Variation in size of wintering larv;e, 
two and one-half times enlarged. Figs. 3-6 slightly enlarged. (Original.) 



U. S. D. A., B. E. Bui. IIS, Part I. D. F. 1. 1., August <J, 1912. 

PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



LIFE-HISTORY STUDIES ON THE CODLING MOTH IN 

MICHIGAN. 

By A. G. Hammar, 
Entomological Assistant. Deciduous Fruit Insect Investigations. 

INTRODUCTION. 

During the last four years the Bureau of Entomology has main- 
tained a temporary held station at Douglas, Mich., for the purpose of 
investigating certain deciduous fruit insects. As a part of this work 
the present paper brings together the results for 1909, 1910, and 1911 
of a detailed study of the life history of the codling moth (Carpocapsa 
pomonella L.). This investigation has been conducted on the general 
plan of the earlier work on this insect by the bureau as reported in 
1909 by E. L. Jenne in the Ozarks and in 1910 by the writer in 
Pennsylvania. 

During the season of 1909 the rearing work was carried out by 
Messrs. R. W. Braucher and W. Postiff; in 1910 and 1911 by the 
writer, assisted by Mr. E. R. van Leeuwen. In 1911 Mr. E. H. 
Siegler was also detailed to assist in the rearing work and has in 
addition aided the writer in the preparation of the manuscript tables. 
Mr. E. W. Scott, conducting various spraying experiments at the 
field station, has contributed valuable field observations. The writer 
wishes to express special thanks to many of the fruit growers of the 
Michigan fruit belt, who have facilitated this work both with valuable 
information and numerous courtesies, and to Prof. A. L. Quaintance, 
in charge of deciduous fruit insect investigations, whose practical 
suggestions throughout the course of this work have been of great aid. 

A duplication of many rearing experiments for 1910 and 1911 became 
necessary because of the unprecedented seasonal condition during 
the spring of 1910, when the fruit crop was to a very great extent 
destroyed by the sudden alternations from warm to cold weather. 
The season of 1911 was very exceptional for its extreme heal, which 
is strikingly reflected in the rate of development of the insect dining 
that year. The rearing work during the more normal season of 1909 
was greatly limited owing to the stress of other work, and the rearing 
experiments for that season cover merely the more essential features 
of the life history of the codling moth. The results thus gathered 

l 



2 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

under marked seasonal climatic variations become of particular value 
ior comparative study, and through the duplication of certain rearing 
experiments better averages have been established for the time of 
occurrence and the duration of the separate stages of the insect. 

DEFINITION OF TERMS USED. 

By the use of terms which are not well defined or uniformly inter- 
preted confusion is often likely to arise. This is particularly true 
in regard to the terms "brood" and "generation" applied to the 
codling moth. In conformity with previous papers on the codling 
moth the term "brood" is here used in speaking of individuals of one 
generation of any stage, as egg, larva, or pupa. A "generation" is 
considered to begin with the egg stage and to terminate with the moth 
or imago stage of the same generation, thus including all the stages 
of a life cycle. Since the wintering larvae of the codling moth in this 
section of the country are of both the first and the second broods, 
which can be separated only by rearing, they are all referred to as 
"wintering larva?" or "wintering brood of larvae." 

Similarly, the pupae and moths that result from the wintering 
larvae and issue in the spring pertain also to the two broods. It may 
therefore be suitable to use the terms "spring brood of pupae," and 
"spring brood of moths" or briefly "spring pupae" and "spring 
moths." It should be remembered that the first brood of pupae and 
the first brood of moths are actually second to appear during the sea- 
son. For popular purposes to avoid confusion the latter set may be 
called "summer pupae" and "summer moths" and in sections where 
three broods exist the second-brood pupae and moths may be termed 
"fall pupae" and "fall moths." 

The following plan of designating the separate stages has been 
uniformly followed by the bureau in the codling moth investigations: 
The wintering larvse may include larvae of the first, second, and 
third broods. 

The spring brood of pupse may include pupa 1 of the first, second, and 
third broods. 

The spring brood of moths may include moths of the first, second, 
and third broods. 

The first generation includes : 
The first brood of eggs; 

The first brood of larvse, some of which winter; 
The first brood of pupse, some of which transform the same sea- 
son ("summer pupae") and a part the following spring 
("spring pupae"); 
The first brood of moths, some of which emerge the same season 
("summer moths") and some the following spring ("spring 
moths"). 



THE CODLING MOTH IN MICHIGAN. 



3 



The second generation includes : 
The second brood of eggs; 

The second orood of larvae, all or only a part of which may winter ; 
The second brood of pupae, of which a part may transform the 

same season ("fall pupae"), and a part or all the following 
spring ("spring pupae"). 
The third generation includes: 
77/ e third brood of eggs; 

The third brood of larvae, all of which winter as larvae; 
The third brood of pupae, which transform the following spring 

("spring pupae"); 
The third brood of moths, which emerge the following spring 

("spring moths"). 




/ 3 S ? 9 tl /3 'S '7 /? 2' 2$ ** 27 2? / 3 S 7 ? // A3 AT 



Uun 



cAVy 



Fio.l. — Emergency curveof spring brood of moths in 1009, at Douglas, Mich. Rcoordsof R. W. Brauchw. 

(Original.) 

SEASONAL-HISTORY STUDIES OF 1909. 

The records on the life history of the codling moth during 1900 
cover merely the essential features and were all made by Messrs. 
It. W. Braueher and W. Postilf. The experiments were conducted 
in an outdoor rearing shelter, and inasmuch as the rearing material 
was from band-record collections the results should closely represent 
normal conditions. 

TIME OF EMERGENCE OF MOTHS OF THE SPRING BROOD. 



In Table I and figure 1 is given the rate of emergence of 114 indi- 
vidual moths. The period for the maximum emergence is here well 
defined, occurring from June 1 7 to 24. Considering the limited num- 
ber of insects used for this experiment it is very probable that isolated 
moths may have appeared even previous to June 1 and later than 
June 15, since the two broods of moths generally overlap. 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

Table I. — Emergence of moths of the spring brood, Douglas, Mich., 1909. 
[Records by R. W. Braucher.] 



! 

Date. 


Number 

of 
moths. 


Date. 


Number 

of 
moths. 


Date. 


Number 

of 
moths. 


Date. 


Number 

of 
moths. 


June 1 
June 3 
June 4 
June 6 
June 12 


3 
1 
1 

4 
4 


June 13 
June 16 
June 18 
June 20 
June 22 


1 
3 
12 
40 
20 


June 23 
June 24 
June 27 
June 29 
July 4 


16 
2 
2 

1 
2 


July 8 
Jul 15 


1 
1 



Total, 114 moths. 
TIME OF EMERGENCE OF MOTHS OF THE FIRST BROOD. 

The earliest moth of the first brood emerged July 28 (Table II). 
It will be noted from the curve of figure 2 that the maximum of 
emergence occurred unusually early — August 3. Throughout the 
month of August there was a constant and large emergence. The 




F IG . 2. — Emergence curve of first-brood moths in 1909, at Douglas, Mich. (Original.) 

great irregularity of the curve in figure 2 is largely due to the fact 
that the banded trees from which the rearing material was obtained 
were only examined once a week. However, certain of the irregu- 
larities of the curve are due to climatic influences. 

Table II. — Emergence of moths of the first brood or summer brood at Douglas, Mich., 19G9. 

[Records by W. PostifT.] 



Date. 


Number 

of 
moths. 


Date. 


Number 

of 
moths. 


Date. 


Number 

of 
moths. 


Date. 


Number 
of 

moths. 


July 28 
July 29 
July 30 
July 31 
Aug. 1 
Aug. 2 
Aug. 3 
Aug. 4 
Aug. 5 
Aug. 6 
Aug. 7 
1 


1 
2 
3 
1 
2 
3 
17 
14 
10 
5 
12 


Aug. 8 
Aug. 9 
Aug. 10 
Aug. 11 
Aug. 12 
Aug. 13 
Aug. 14 
Aug. 15 
Aug. 16 
Aug. 17 
Aug. 18 


15 
8 
5 
7 
2 
1 
7 


Aug. 19 
Aug. 20 
Aug. 21 
Aug. 22 
Aug. 23 
Aug. 24 
Aug. 25 
Aug. 20 
Aug. 27 
Aug. 28 
Aug. 29 


8 
1 
3 


Aug. 30 
Aug. 31 
Sept. 1 
Sept. 2 
Sept. 3 
Sept. 4 
Sept. 5 
Sept. 6 
Sept. 7 
Sept. 8 
Sept. 13 


1 
2 
1 
1 
4 
3 




2 
10 
5 
2 
2 
4 




12 
5 
8 




4 

1 



Total, 194 moths. 



THE CODLING MOTH IN MICHIGAN. 



BAND-RECORD EXPERIMENTS IN 1909. 



In the band-record experiments of 1909, 30 apple trees were used, 
of which 15 trees were located in the yard of the laboratory and 16 
trees in two near-by orchards. Fall and winter apples, such as Rhode 
Island Greening, Baldwin, Golden Russet, Northern Spy, Wealthy, 
etc., were used. With these late varieties of apple a thorough test 
was made of the relative abundance of first and second brood larvae. 
The results of these experiments are recorded in Tables III and IV 
and by curves in figure 3. 




Fig. 3. — Curves shoving maturity of larvse of first and second broods; band-record curve, of 1909, at 

Douglas, Mich. (Original.) 

Table III.— Band-record experiments in 1909 at Douglas, Mich., by W. Postiff; com- 
pleted in 1910 by . I. (',. I laminar. 



No. of 
record. 


Date of col- 
lecting. 


Number 
of larvae 

and 
pupae. 


Number 

of moths 

emerged, 

1909. 


Number 
Of para- 
sites, 
1909. 


Numbcr 

df moths 

emerged, 

1910. 


Number 

of para- 
sites, 
1910. 


Injured 
and win- 
ter-killed. 


1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
11 
15 
16 
17 
18 
19 


July 12 
July 19 
July 26 
Aug. 2 
Aug. 9 
Aug. l(i 
Aug. 23 
Aug. 30 
Sept. 6 
Sept. 13 
Sept. 20 
Sept. 27 
Oct. i 
Oct. 11 
Oct. 18 
Oct. 23 
Nov. 1 
Nov. 8 
Nov. 15 

Total 


6 
62 

lit) 
87 
81 
80 
85 
138 
<i2 
124 
174 
213 
124 
94 


6 

49 
49 
41 
30 
17 
1 
1 








4 
6 
5 

2 






,? 

32 
35 
23 
15 
23 
14 
35 
40 
50 
20 
3(3 






13 
36 
61 
110 
47 
88 
119 
137 
92 
55 


2 

4 

8 
4 
1 
1 
15 
26 
12 
3 












































51 
20 
8 






30 
15 
6 


2 
1 


13 
4 
3 














1,475 


194 


17 


821 


80 


3ti3 



5 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

Table IV. — Summary of Table III; band-record experiments at Douglas, Mich., 1909. 



Observations. 


Total. 


Per 

cent. 


Observations. 


Total. 


Per 

oent. 


Larvae and pupae collected from 


1,475 

194 

821 

1,015 

97 


100.0 

13.2 
55.7 
68.8 
6.6 


Injured and winter-killed larvae. . . 


363 
636 

194 

425 
839 


24.6 
43.1 


Moths emerging: 

1909 


Transforming larvae of the first 

brood 

Wintering larvae of the first 


33.2 


1910. . . 




1909-1910 


66.8 




Larvae of the second brood 


56.9 







In numbers the second brood of larvae surpassed the first quite 
materially. From October 18 to 25 no larvae were obtained, due to 
prevailing cold weather. However, during the exceptionally warm 
November quite a number were collected which under average sea- 
sons would have remained undeveloped. Of the first-brood larvae 
43 per cent transformed the same season, while 57 per cent wintered 
together with those of the second brood. Of the total number of 
larvae, 6.58 per cent proved to be parasitized by a hymenopterous 
fly (Ascogaster carpocapsse Vier.). The proportion winter-killed and 
injured by other causes was 24.6 per cent. 

SEASONAL-HISTORY STUDIES OF 1910. 

The rearing material in the spring of 1910 consisted of an abun- 
dance of wintering larvae, which had been collected from banded 
trees during the previous season. During the winter and throughout 
the progress of the rearing experiments the insects were kept in cages 
in an outdoor shelter (see Plate II), and were thus exposed to the 
normal temperature conditions. 

WINTERING LARV^. 

The wintering larvae invariably consist of individuals of the two 
broods, as only a portion of the first brood transforms the same season 
to form the second generation of moths, while the other portion win- 
ters like all of the second-brood larvae. 

In the orchards a great number of the wintering larvae find protec- 
tion for their cocoons under the rough bark of the trees and in cracks 
and crevices in older trees, and many are frequently found imbedded 
in decayed wood. It is mainly in the latter places that the codling 
moth larvae find an escape from woodpeckers and other birds which 
make persistent searches for the larvae during the winter. 

The cocoon of the wintering larva. — The winter cocoon of the larva 
is proportionately small and completely sealed, and consists of heavy 
walls for winter protection. In appearance these cocoons vary con- 
siderably, depending largely upon the place selected by the larvae. 
Under loose bark, where the larvae are not limited in space, the co- 
coons are more or less oval, as shown in Plate I, figure 3. A slight 



Bui. 1 15, Part I, Bureau of Entomology. U. S. Dept. of Agriculture. 



Plate II 




THE CODLING MOTH IN MICHIGAN. 7 

depression is made in the bark, the walls along the exposed sides are 
constructed from fragments of bark held in place by silken threads, 
and the inside is finally lined with a thin layer of silk. Within the 
small space of the cocoon the larva will be found in a doubled-up posi- 
tion. In the spring, previous to pupation, the winter cocoon is partly 
remodeled by the larva (see PI. I, fig. 4), and provision is made for 
the issuing moth by the construction of an exit tube (see PI. T, 
fig. 5). This is partly made from fragments of the original wall of 
the cocoon and partly by the addition of new fragments of bark. 
Depending upon the location of the cocoon, the exit tube varies in 
length from one-fourth of an inch to over 1 inch. The purpose of the 
tube must be to provide a safe exit at the critical period of the emer- 
gence of the moth. Within the cocoon over the opening to the exit 
is placed a thin sheath of silk which is ruptured by the pupa at the 
time it wriggles out (see PI. I, fig. 6) to give issuance to the moth. 

The transforming larvae of the first brood also make their cocoons 
with an exit tube. The cocoons of these larvae, however, are only 
used for a short time and are hence of a more primitive construction. 

Variation in size of wintering larvae. — In size the wintering larvae vary 
considerably (see PI. I, fig. 7). There exists naturally a certain 
amount of individual variation, but in addition there are climatic 
factors which tend to increase this variation. The wintering larvae 
of the first brood are for the most part fully developed. There seems 
to be a tendency for undersized larva 1 , to transform the same season, 
as if less fit to pass the winter. Of the second-brood larva' there are 
always a number that fail to attain full growth in the fall, and others 
totally fail to enter hibernation before frost sets in. Larvae para- 
sitized by Ascogaster carpocapsse are seldom more than half grown 
and lack the pink color of the healthy larva. 

Judging from the uniformity of head measurements, the wintering 
larvae, though variable in size, are probably to a great extent of the 
last or sixth instar. (See p. 78.) 

Winter-killed larvae. — In earlier studies of the codling moth the 
writer has noted that killing due to cold occurred more or less fre- 
quently among wintering larvae. During the spring of 1910 and 1911 
more definite data were obtained showing a rather high percentage 
of winter killing. Thus, of the total number of larvae from the band 
records of 1909 (Tables III and IV), 27.6 per cent failed to develop. 
A mortality of about 4 per cent may be ascribed to injury from the 
handling of the insects, while the rest, 20 per cent, succumbed mainly 
to injury from cold. Under normal conditions in orchards the per- 
centage of larvae killed from cold is undoubtedly lower than the 
above figures because a proportionately large number is always 
destroyed during the winter by woodpeckers and nuthatches and in 
the spring, summer, and fall by predaceous insects and parasites. 



8 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



It is quite noticeable that larvae in exposed places or in poorly con- 
structed cocoons are more frequently killed by cold than are those 
well protected. 

As generally recommended under the control of the codling moth, 
it will be well worth while in orchards to eliminate the favorable hiding 
places of the larvae, particularly the wintering brood. Such places 
are old stumps, decaying trunks, and branches of ill-kept trees, where 
cold weather little affects the larva? or where their enemies can not 
readily reach them. 

SPRING BROOD OF PUPvE. 

Methods of recording pupation. — On account of the fact that pupa- 
tion takes place within the cocoon it is often difficult to record this 
transformation without disturbing the insect by exposing the cocoon. 




Fig. 4. — Device used in obtaining pupal records of the codling moth. (Original.) 

Different workers have often used small glass vials, within which 
the larvae have been compelled to make their cocoons and transform. 
This method is veiy unsatisfactory when we consider the habit of the 
larvae under normal conditions. The larva, in the construction of 
the cocoon, either in cracks of wood or under the bark of trees, gnaws 
off a certain quantity of particles of wood or bark and from these the 
cocoon is largely made. Furthermore, under normal protection the 
larva suffers less from outside fluctuating temperatures than might 
be expected in a tube of glass. 

Formerly the writer used soft strips of wood with narrow inter- 
spaces of one-eighth of an inch which the larvae could enter and there 
spin their cocoons. To observe the larvae and pupae within it was 
necessary to pull the strips apart, thus exposing the cocoon. Later 
it was found that when a thin film of transparent celluloid was placed 
in the interspace so as to cover the wood on one side the larvae pro- 
duced their cocoons in a normal manner and at the same time left the 



THE CODLING MOTH IN MICHIGAN. 



side against the celluloid more or less uncovered, so that the insects 
could be observed within their cocoons without disturbing the latter. 
Some larvae, however, particularly when exposed to too much light, 
would line with silk the side of the cocoon against the film. The diffi- 
culty in such cases was overcome by cutting in the film over the 
cocoon a small lobe or flap which could be gently lifted for the neces- 
sary exposure. This device is illustrated in figure 4. The upper 
figure shows the lower side with numbers corresponding to the posi- 
tion of the cocoons within. In the central figure several larvae anil 
cocoons are seen protected by the celluloid film. The two strips of 
wood are held together by a pair of common paper clips which have 
been bent and adjusted to the shape desired. 




b 1 12 IS IS 21 24 

June 



FiG.5.— Diagram showing time of spring pupation of the codling moth in 1910, at Douglas, Mich. (Original.) 

Time of pupation. — Owing to the very warm weather during the 
spring, pupation had commenced by April 15 (see fig. 5). However, 
with a change to cold weather that followed, pupation was inter- 
rupted until the latter part of May, and most of the larvae pupated 
during the brief period from May 19 to May 31. The last pupa of 
this brood appeared on June 23. (See Table V.) 

Table V. — Pupation period/or the codling moth in the spring of 1910, at Douglas, Mich. 



No. of 


Date of 


No. of 


Date of 


No. of 


Date of 


No. of 


Date of 


lame. 


pupation. 


larva-. 


pupation. 


larvse. 


pupation. 


larva\ 


pupation. 


2 


Apr. 15 


5 


May 25 


2 


June 4 


4 


Juno 14 


1 


Apr. 30 

May (i 


3 


May 26 


o 


June 5 


3 


June 15 


1 


2 


May 27 


1 


June (i 


2 


June 17 


4 


May 19 


9 


May 28 


■_' 


June 7 


2 


June 19 


1 


May 20 


8 


May 29 


2 


June S 


1 


June 22 


21 


May 21 


4 


May 31 


1 


June 9 


'-' 


June 23 


14 


May 22 


1 


June 1 


4 


June 10 






13 


May 23 


o 


June 2 


3 


June 12 






5 


May 24 


- 


June 3 


1 


June 13 







10 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Length of spring pupal stage. — The results of observations on the 
time of pupation and emergence of 106 individual insects are given 
in Table VI. Those pupating in April remained in this stage for the 
exceptionally long period of 59 days. The majority, pupating during 
the latter half of May, remained in the pupal stage about 30 days, 
wliile later larva?, pupating about June 15, remained in this stage 
only 10 to 15 days. (See Table VI.) The average for the entire 
spring brood of pupae was 26.02 days. 

Table VI. — Length of pupal stage of the spring brood, Douglas, Mich., 1010. 





Date of— 










No. of 








No. of 








obser- 








obser- 






Days. 












vation. 


Pupation. 


Emergen 


•r. 


vation. 


Pupation. 


Emergence. 




1 


Apr. 15 


June 1 


1 59 


54 


May 25 


June 22 


28 


2 


Apr. 30 


June 1 


> 46 


55 


...do 


...do 


28 


3 
4 


May 6 
May 19 


June 1 
June 1 


7 42 
i 30 


56 

57 


...do 


...do.... 


28 
28 


...do 


...do 


5 


...do 


Juno 1 


1 31 


58 


...do 


June 23 


29 


6 


...do 


...do.... 


31 


59 


May 26 


June 22 


27 


7 


...do 


June 2 


1 32 


60 


...do 


...do 


27 


8 


Mav 20 


...do.... 


31 


61 


...do 


June 23 


28 


9 


May 21 


June 1 


i 28 


62 


May 27 


June 22 


26 


10 
11 


...do 
...do 


Juno 1 
June 2 


) 29 
) 30 


63 
64 


...do 


...do 


26 
25 


May 28 


...do 


12 


...do 


...do.... 


30 


65 


...do. 


...do 


25 


13 
14 


...do 


...do.... 


30 
30 


66 
67 


...do 


...do.... 


25 
26 


...do 


...do.... 


...do 


June 23 


15 


...do 


...do.... 


30 


68 


...do 


...do 


26 


16 


...do 


...do.... 


30 


69 


...do 


...do 


26 


17 


...do 


...do.... 


30 


70 


...do 


...do 


26 


18 


...do 


June 2 


31 


71 


...do 


...do 


26 


19 


...do 


...do.... 


31 


72 


Mav 29 


June 19 


21 


2ft- 


..do 


...do.... 


31 


73 


...do 


June 23 


25 


21 
22 


...do.... 


...do.... 


31 
31 


74 
75 


do.... 


do 


25 
25 


...do 


...do.... 


...do 


...do 


23 


...do 


...do.... 


31 


76 


...do 


...do 


25 


24 


...do 


...do. ... 


31 


77 


Mav 31 


...do 


23 


25 
26 


...do 


...do.... 


31 

> 32 


78 
79 


...do 

June 1 


...do 

...do 


23 
22 


...do 


June 2 


27 


...do 


June 2 


: P 34 


80 


June 2 


...do 


21 


28 


Mav 22 


June 2 


30 


81 


...do 


June 24 


22 


29 


...do 


...do.... 


33 


82 


June 3 


June 23 


20 


30 
31 


...do 


...do.... 


30 
30 


83 
84 


...do 
June 4 


June 24 
June 23 


21 
19 


...do 


...do.... 


32 


...do 


...do.... 


30 


85 


June 5 


...do 


18 


33 


...do 


...do.... 


30 


86 


...do 


...do 


IS 


34 


...do 


...do.... 


30 


87 


June 6 


...do 


17 


35 
36 
37 
38 


...do 


...do.... 


30 

30 

30 

! 31 


88 
89 
90 
91 


June 7 
...do 


June 24 
...do 


17 
17 
16 
16 


...do 


...do.... 


...do 


...do.... 


June 8 
June 9 


...do 

June 25 


...do 


June 2: 


39 


...do 


June 2.' 


I 32 


92 


June 10 


June 20 


10 


40 
41 


...do.... 


...do.... 


32 
L 29 


93 
94 


...do 
...do 


June 24 
June 25 


14 
15 


Mav 23 


June 2 


42 


...do 


...do.... 


29 


95 


...do 


June 26 


16 


43 


...do 


...do.... 


29 


96 


June 12 


...do 


14 


44 


...do 


June 2'. 


5 30 


97 


...do 


June 27 


15 


45 


...do 


...do.... 


30 


98 


...do 


...do 


15 


46 


...do 


...do.... 


30 


99 


June 13 


...do 


14 


47 
48 
49 


...do 


...do.... 


30 
30 
30 


100 
101 
102 


June 14 
...do 
June 15 


Juno 28 
June 29 
June 28 


14 
15 
13 


...do 


...do.... 


...do 


...do.... 


50 


...do 


...do.... 


30 


103 


...do 


June 29 


14 


51 


May 24 


...do.... 


29 


104 


June 17 


July 2 


15 


52 
53 


...do 


...do.... 


- 29 
35 


105 

106 


June 19 
June 23 


June 29 
July 8 


10 
15 


...do 


June 2? 


Average 


26. 02 
















59 

10 































THE CODLING MOTH IN MICHIGAN. 



11 



Table VII. — Length of pupal stage of the spring brood, Douglas, Mich., 1910; sum- 
mary of Table VI. 



Num- 




Num- 




Num- 




Num- 




ber of 


Pupal 


ber of 


Pupal 


ber of 


Pupal 


ber of 


Pupal 


obser- 


period. 


obser- 


period. 


obser- 


period. 


obser- 


period. 


vations. 




vations. 




vations. 




vations. 






Days. 




Days. 




Dai/s. 




Days. 


2 


10 


1 


19 


2 


27 


1 


35 


1 


13 


1 


20 


6 


28 


1 


42 


5 


14 


3 


21 


7 


29 


1 


46 


(i 


15 


2 


22 


25 


30 


1 


59 


3 


16 


2 


23 


12 


31 






3 


17 


i 


25 


4 


32 






2 


18 


7 


26 


1 


34 







SPRING BROOD OF MOTHS. 

Time of emergence (fig. 6, p. 12). — Notwithstanding the changeable 
weather conditions during the spring of 1910 the codling moths 
emerged with striking uniformity. The earliest moth in the rearing 
cages appeared June 13 ; the great majority of moths emerged between 
June 18 and June 30; isolated moths continued to appear up to the 
close of July, when the first moths of the summer brood commenced 
to issue. The maximum emergence took place June 22. The emer- 
gence for the spring brood is given in Table VIII. 

Table VIII. — Time of emergence of the spring brood of moths during 1910, at Douglas, 

Mich. 



Num- 
ber of 
moths. 


Date of 
emergence. 


Num- 
ber of 
moths. 


Date of 
emergence. 


Num- 
ber of 
moths. 


Date of 
emergence. 


Num- 
ber of 
moths. 


Date of 
emergence. 


5 

5 

1 

4 

17 

40 

52 

82 

162 

232 

199 

128 


June 13 
June 14 
June 15 
June 16 
June 17 
June 18 
June 19 
June 20 
June 21 
June 22 
June 23 
June 24 


59 
56 
81 
36 
45 
53 
33 
34 
19 
9 
10 
10 


June 25 
June 26 
June 27 
June 28 
June 29 
June 30 
July 1 
July 2 
July 3 
July 4 
July 5 
Julv 6 


7 
6 

(■; 

5 
8 

ti 

6 


July 7 
Julv 8 
July 9 
July 10 
July 11 
July 12 
July 13 
July 14 
July 15 
July 16 
Julv 17 
July 18 


2 
1 

2 


July 19 
July 20 
July 21 
July 22 
July 23 
July 24 
July 25 
July 26 
Julv 27 



Variation in size of moths of the spring brood. — The moths of the 
spring brood vary considerably in size and to a greater extent than 
do those of the summer brood. (See PI. I, fig. 1.) This might be 
expected on considering the difference in size of the wintering larvae 
from which the moths result. 

There have often appeared dwarfed specimens of moths from the 
band-record material which at first sight could hardly be recognized to 
be of the codling-moth species. That there should exist a correspond- 
ing difference in the vitality of individual moths is only natural and is 
fully reflected in many of the results of the rearing experiments. In 
view of the great variability in behavior of the insect it has been 
necessary to conduct many of the experiments on a large scale in 
order to establish reliable averages. 
35215°— Bull. 115, pt 1—12 2 



12 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Time of oviposition. — The time of oviposition in orchards may be 
determined with fair precision from the combined data on the habits 
of the moths in captivity, the rearing experiments, and the field 
observations. In rearing these insects eggs may be readily obtained 
by confining a number of moths together in cages. It is not possible 
to determine the number of eggs thus produced, but the time and 
period of egg deposition can be ascertained. 




12.14 It 18 20 22 24 2t 2.8 30 2 4 b 8 10 12 14 fa IS 20 22 24 Zb 28 

June July 



Fig. 6.— Emergence curve of spring brood of moths in 1910, at Douglas, Mich. (Original.) 

Table IX. — Egg deposition of the spring brood of moths in cages in 1910, at Douglas, 

Mich. 



No. of 
cage. 


Num- 
ber of 
moths. 


Date of — 


Number of days — 


Emergence. 


First 
oviposi- 


Last 
oviposi- 


Before 

first 

ovipo- 


Of egg 
deposi- 


From 
date of 
emer- 
gence 








tion. 


tion. 


tion. 


to last 
















oviposi- 
















tion. 


1 


5 


June 14 


June 19 


June 21 


5 


3 


7 


2 


3 


June 16 


June 20 


do 


4 


2 


5 


3 


15 


June 17 


June 19 


Juno 25 


2 


7 


8 


4 


36 


June 18 


June 20 


June 20 


2 


7 


8 


5 


57 


June 19 


do 


June 27 


1 


.8 


8 





87 


June 20 


June 23 


June 29 


3 


7 


9 


7 


262 


June 22 


do 


July 4 


1 


12 


12 


8 


25 


June 24 


June 29 


July 2 


5 


4 


8 


9 


29 


June 25 


do 


July io 


4 


12 


15 


10 


27 


June 27 


July 2 


July 7 


."> 


6 


10 


11 


16 


June 2S 


July 1 


July 3 


3 


3 


5 


12 


24 


June 29 


July 2 


July 10 


3 


9 


11 


13 


36 


June 30 


July 3 


July 9 


3 


7 


9 


14 


25 


July 2 


July 9 


do 


7 


1 


i 


15 


8 


July 6 


July 8 


July 11 


2 


4 


5 


lfi 


5 


July 9 


July 11 


do 


2 


1 


2 


17 


5 


July 11 


July 14 


July 14 


3 


1 


3 


Aver; 


go numl 








3.24 


5.53 


7.76 


Maxii 
Minin 


mm inn 
mm nun 


nbor of days 
iber of days. 






/ 
1 


12 
1 


15 
2 











THE CODLING MOTH IN MICHIGAN. 



13 



111 Table IX are given the results from 17 separate "stock-jar" 
experiments, so called because of the nature of these experiments. 
Medium-sized glass jars of about 1 gallon capacity were found to be 
well suited for the purpose. To provide for a certain amount of 
moisture a layer of damp sand was put in each jar; food was fur- 
nished the moths in the form of diluted sugar and honey solution 
placed on a small piece of sponge. In each cage a certain number of 
moths, of known date of emergence, was confined, and throughout 
the course of the experiments a daily record was kept of egg deposi- 
tion and the length of life of the moths. The eggs were laid indis- 
criminately all over the cage, on the sand, on the sides of the glass, 
on apple foliage and fruit, and on the cloth cover of the jars. 
When too many moths were confined together eggs were even placed 
on the wings and backs of some of the moths. For the purpose of 
recording the egg stage it was found desirable to have the moths 
oviposit on pear leaves in place of fruit because the leaves darken 
upon withering, so that the light-colored semitransparent eggs may 
be better observed. Each day fresh foliage was placed in the cages, 
which insured eggs of a given date of deposition. 

On an average the moths commenced to oviposit three days after 
the date of emergence and most of the eggs were laid within a 
week of emergence. In a few extreme cases eggs were laid the 
second day after emergence. In one instance the last eggs were 
laid 15 days after the date of emergence. (See Table IX.) Several 
moths in the stock jars survived from 19 to 25 days. 

Length of life of moths. — A summary of observations on the life of 
529 moths is given in Tables X and XI. The average length of life 
was 9.44 days, the maximum 25 days, and the minimum 2 days. 
These moths were from the stock-jar experiments previously de- 
scribed. 

Table X. — Summary of observations on the length of life of 529 moths of the spring 
brood in confinement, Douglas, Mich., 1910. 



Number 


Number 


Number 


Number 


Number 


Number 


Number 


Number 


of moths. 


of days. 


of moths. 


of days. 


of moths. 


of days. 


of moths. 


of days. 


S 


2 


118 


8 


GO 


13 


9 


18 


1 


3 


hi 


9 


14 


14 


6 


19 


g 


5 


47 


10 


7 


15 


1 


20 


74 





28 


11 


9 


16 


1 


25 


70 


7 


44 


12 


8 


17 







Table XI. — Summary of Table X. Length of life of moths of the spring brood, 1910. 





Days 
alive. 




9.44 
25 
2 




Minimum 





14 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



THE FIRST GENERATION. 

FIRST BROOD OF EGGS. 

Length of incubation. — The eggs of the first brood on an average 
hatched within 6 or 7 days. Under low temperature the maximum 
length of time was 10 days. The shortest period of incubation was 
4 days. (See Table XII.) 

Table XII. — Incubation period of eggs of the first brood laid in rearing cages, Douglas, 

Mich., 1910. 









Date of — 




Duration of— 


No. of 
obser- 


Date of 
egg depo- 














Appear- 


Appear- 




Red 


Black 


Incu 


vation. 


sition. 


ance of red 
ring. 


ance of 
black spot. 


Hatching. 


ring. 


spot. 


bation. 












Days. 


Days. 


Days. 


1 








June 29 






9 


2 
3 
4 


do 






June 30 
June 29 

June 30 
July 1 






10 

7 
8 
7 


June 22 
do 




June 28 
...do 




6 
6 




















July 2 






7 










...do 






6 










July 3 






6 


9 . 
10 








Julv 4 






6 


do 






Julv 5 






7 


11 


June 29 




Julv 3 


July 4 




4 


5 


12 






...do 


Jlllv 5 




4 


6 


13 


June 30 


July 3 


July 5 


July 6 


3 


5 





14 


...do 


...do 


...do 


July 7 


3 


5 


7 


15 


July 1 


...do 


July 6 


..do 


2 


5 


6 


1(5 


...do 


...do 


...do 


July 8 


2 


5 


7 


17 


July 2 


July 5 


Julv 7 


..do 


3 


5 


6 


18 


July 3 


July 


July S 


July 9 


3 


5 


6 


19 


...do. 


...do 


...do 


July 10 


3 


5 


7 


20 


July 4 


...do 


July 9 


...do 


2 


5 


G 


21 
22 


do. 


...do 


July 10 
July 11 


July 12 
July 13 


2 
3 


6 
5 


8 

7 


July 6 


July 9 


23 


...do 


...do 


...do 


July 14 


3 


5 


8 


24 


July 7 


...do 


...do 


July 13 


2 


•± ' 


6 


25 


July 8 


July 10 


July 12 


July 14 


2 


4 


6 


26 


July 9 


July 12 


July 14 


July 15 


3 


5 


6 


27 


...do. 


July 13 


...do 


Julv 16 


4 


5 


7 


28 


July 12 


July 14 


July 15 


...do 


2 


3 


4 


29 


...do 


...do 


...do 


July 17 


2 


3 





30 


do 


...do 


July 16 


July 18 


2 


4 


6 








2.5 


4.7 


6.6 




4 


6 


10 












2 


3 


4 












1 



The so-called "red ring" of the egg appeared from two to three days 
after egg deposition, and the "black spot" from one to two days pre- 
vious to hatching. 

The eggs used in these experiments were laid hi cages on pear 
foliage. Records on the development of the eggs were taken once 
daily between 9 and 10 o'clock in the morning. 

FIRST BROOD OF LARVAE. 

Time of hatching. — In the field the actual time of hatching and the 
relative abundance of newly hatched larva? may be fairly well deter- 
mined from the different data on hand relative to the time of emer- 
gence of the moths, egg deposition, incubation of eggs, length of 
feeding of larvae, and the appearance of mature larvae, as shown by the 
band records. In correlating these facts the time of hatching is estab- 
lished as given in the diagram of figure 11. 

The earliest eggs were deposited June 17, the maximum oviposition 
was reached at the close of June, and a few late eggs were laid up to 



THE CODLING MOTH IN MICHIGAN. 15 

the end of July. Incubation of the earliest eggs lasted nine days; 
for eggs laid about June 30, six days; and for later ones laid during 
the middle and latter part of July, only four to five days. The 
larvae from the Saugatuck band records (fig. 9) reach a maximum 
Juh' 31, and inasmuch as the average length of feeding for this brood 
of larvae was 27 days the date for the maximum hatching would be 
July 4. On the other hand, on the basis of oviposition and length 
of incubation the height of the hatching period would be July 6. 

Length of feeding. — Reference has already been made in the pre- 
vious pages to the fact that a portion of the first-brood larvae do 
not transform the same year, but winter and complete the life cycle 
the following year. The transforming and wintering larvae differ 
in the length of feeding, and the latter are often materially larger 
in size. Thus on an average the transforming larvae remained in 
the fruit 25 days against 29 days for the wintering larvae. (See 
Tables XVI and XVII.) For the entire brood of larvae the shortest 
feeding period was 17 days, the longest 45 days. 

Tirrn of maturity of larvse,.— -In the field the time of maturity of 
the larvae is determined from the band-record experiments (fig. 9 
and Table XXVIII). Thus the period for the first-brood larvae 
at Douglas, Mich., extended from July 10 to September 10. After 
the emergence of the moths from the band-record collection it may 
further be possible to determine the time of maturity of transforming 
and wintering larvae of this brood. The last transforming larva 
left the fruit August 8 and the first wintering larvae left the fruit 
July 20. Tnere is also a difference in the appearance of cocoons 
whereby the two sets of larvae may be recognized; the transforming 
larva provides the cocoon with an exit tube, while the wintering 
larva produces a closed cocoon. (For full description see pp. 6-7.) 

Percentages of transforming and wintering larvse. — From Table 
XXXI it will be found that 201 larvae of the first brood transformed 
the same season, while 368 wintered, or 35 per cent transformed 
and 64.1 per cent wintered. 

Somewhat similar results were obtained from the rearing experi- 
ments, though these can not be as reliable as the data from the 
band-record experiments, since the former are from a limited num- 
ber of observations. Out of a total of 51 larvae, 21 transformed 
and 30 wintered, or 40 per cent transformed and 60 per cent wintered. 
(See Table XXII.) 

Larval life in the cocoon. — The length of time required for the 
making of the cocoon depends largely upon whether the larva is to 
transform the same season or to winter. A slight individual varia- 
tion of time naturally does exist for either set of larvae. In case 
of wintering larvae it is difficult to decide just when the cocoon is 
completed. The transforming larvae cease to be active from two 
to three days before pupating. For these, then, the larval life 
in the cocoon can be readily determined, being considered as the 
period from the time of leaving the fruit to the time of pupation. 



16 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



In Table XIII are given the results from observations on 117 indi- 
vidual insects. Further records on the same topic are found in 
Table XVI. The larval life in the cocoon varied from 3 to 15 days 
with an average of 7 days. In case of a very short period of from 
3 to 5 days the larvae abandoned its first cocoon and made a new 
one. The records, however, only show the time consumed for 
the making of the last cocoon. Such cocoons are very primitive 
in appearance and have not been completed. 

Table XIII. — Length of the pupal stage of the first brood, Douglas, Mich., 1910. 





Date of — 












Date of— 






No. of 

obser- 








Lar- 
vae in 


Pu- 
pal 


No. of 
obser- 






Lar- 
vae in 


Pu- 
pal 














vation. 


Leaving 


Pupa- 


Emer- 


coc- 
oon. 


pe- 
riod. 


vation. 


Leaving 


Pupa- 


Emer- 


coc- 
oon. 


pe- 
riod. 




fruit. 


tion. 


gence. 








fruit. 


tion. 


gence. 














Days. 


Days. 










Days. 


Days. 


1 


July 22 


July 25 


Aug. 9 


3 


15 


60 


July 29 


1 Aug. 4 


Aug. 20 


6 


16 


2 


...do.... 


July 26 


...do 


4 


14 


61 


July 30 


...do 


Aug. 17 


5 


13 


3 


...do 


...do 


...do 


4 


14 


62 


...do 


...do 


...do 


5 


13 


•1 


...do.... 


...do 


...do 


4 


14 


63 


...do 


...do 


...do 


5 


13 


5 


...do 


...do 


Aug. 13 


4 


18 


64 


...do 


...do 


Aug. 18 


5 


14 


6 


...do 


...do 


Aug. 15 


4 


20 


65 


...do 


...do 


...do 


5 


14 


7 


...do 


...do.... 


...do 


4 


20 


66 


...do 


...do 


...do 


5 


14 


8 


...do 


...do.... 


Aug. 20 


4 


25 


67 


...do 


...do 


...do 


5 


14 


9 


...do 


Aug. 6 


Aug. 19 


15 


13 


68 


...do 


...do 


Aug. 19 


5 


15 


10 


...do 


...do 


Aug. 20 


15 


14 


69 


...do 


...do 


Aug. 21 


5 


17 


11 


July 23 


July 29 


Aug. 13 


6 


15 


70 


...do 


Aug. 5 


Aug. 18 


6 


13 


12 


...do.... 


Aug. 4 


Aug. 17 


12 


13 


71 


...do.... 


Aug. 6 


...do 


7 


12 


13 


...do 


...do.... 


...do 


12 


13 


72 


...do 


...do.... 


Aug. 21 


7 


15 


14 


July 25 


July 30 


Aug. 15 


5 


16 


73 


...do 


Aug. 7 


Aug. 18 


8 


11 


15 


...do 


Aug. 1 


...do 


7 


14 


74 


...do 


Aug. 9 


Aug. 21 


10 


12 


16 


...do 


Aug. 3 


...do 


9 


12 


75 


...do 


...do 


...do.... 


10 


12 


17 


...do 


...do.... 


...do 


9 


12 


76 


...do 


...do 


...do 


10 


12 


18 


...do.... 


...do.... 


Aug. 16 


9 


13 


77 


...do 


...do 


Aug. 24 


10 


15 


19 


...do 


...do.... 


...do 


9 


13 


78 


July 31 


Aug. 4 


Aug. 17 


4 


13 


20 


July 26 


...do 


...do 


8 


13 


79 


...do 


...do 


...do 


4 


13 


21 


...do 


...do 


...do 


8 


13 


80 


...do 


J., .do.... 


Aug. 18 


4 


14 


22 


...do 


...do 


...do 


8 


13 


81 


...do 


Aug. 5 


...do 


5 


13 


23 


...do 


...do 


...do 


8 


13 


82 


...do 


Aug. 6 


Aug. 19 


6 


13 


24 


...do 


...do 


...do 


8 


13 


83 


...do 


...do 


Aug. 20 


6 


14 


25 


...do 


...do.... 


Aug. 18 


8 


15 


84 


...do 


Aug. 7 


...do 


7 


13 


26 


...do 


Aug. 4 


Aug. 17 


9 


13 


85 


...do 


!... do.... 


Aug. 21 


7 


14 


27 


July 27 


Aug. 3 


Aug. 13 


7 


10 


86 


...do 


! Aug. 9 


Aug. 22 


9 


13 


28 


...do 


...do 


Aug. 15 


7 


12 


87 


...do 


|...do 


...do.... 


9 


13 


29 


...do 


...do 


...do.... 


7 


12 


88 


Aug. 1 


Aug. 4 


Aug. 18 


3 


14 


30 


...do 


...do 


...do 


7 


12 


89 


...do 


Aug. 5 


Aug. 19 


4 


14 


■31 


...do 


...do 


...do.... 


7 


12 


90 


...do 


Aug. 6 


Aug. 18 


5 


12 


32 


...do.... 


...do 


Aug. 16 


7 


13 


91 


...do 


...do 


Aug. 19 


5 


13 


33 


...do.... 


...do.... 


...do 


7 


13 


92 


...do 


...do 


Aug. 20 


5 


14 


34 


...do 


...do.... 


...do 


7 


13 


93 


...do 


...do 


...do 


5 


14 


35 


...do 


...do.... 


Aug. 18 


7 


15 


94 


...do 


...do 


...do.... 


5 


14 


36 


...do 


...do 


...do 


7 


15 


95 


...do 


Aug. 8 


Aug. 21 


7 


13 


37 


...do 


Aug. 4 


Aug. 15 


8 


11 


96 


...do 


Aug. 9 


...do 


8 


12 


38 


...do 


...do 


Aug. 18 


8 


14 


97 


...do 


...do 


Aug. 22 


8 


13 


39 


...do 


Aug. 6 


Aug. 20 


10 


14 


98 


Aug. 4 


Aug. 12 


...do 


8 


10 


40 


July 28 


Aug. 3 


Aug. 15 


6 


12 


99 


...do 


Aug. 13 


Aug. 25 


9 


12 


41 


...do 


...do 


Aug. 16 


6 


13 


100 


...do 


Aug. 14 


Aug. 26 


10 


12 


42 


...do 


...do 


...do 


6 


13 


101 


...do 


Aug. 15 


Aug. 29 


11 


14 


43 


...do 


...do 


Aug. 17 


6 


14 


102 


...do 


...do 


Aug. 30 


11 


15 


44 


...do.... 


Aug. 4 


...do 


7 


13 


103 


Aug. 5 


Aug. 13 


Aug. 24 


8 


11 


45 


...do.... 


...do.... 


...do 


7 


13 


104 


...do 


Aug. 14 


Aug. 25 


9 


11 


46 


...do.... 


...do 


...do 


7 


13 


105 


...do 


Aug. 17 


Aug. 30 


12 


13 


47 


...do 


...do 


Aug. 18 


7 


14 


106 


Aug. 7 


Aug. 15 


Aug. 27 


8 


12 


48 


...do 


...do.... 


...do 


7 


14 


107 


Aug. 8 


Aug. 14 


Aug. 25 


6 


11 


49 


...do 


...do 


...do 


7 


14 


108 


...do 


Aug. 15 


Aug. 24 


7 


9 


50 


...do 


...do 


...do 


7 


14 


109 


...do 


Aug. 16 


Aug. 30 


8 


14 


51 


...do 


Aug. 5 


Aug. 19 


8 


14 


110 


...do 


Aug. 17 


Sept. 1 


9 


15 


52 


...do 


...do.... 


...do.... 


8 


14 


111 


...do.... 


...do 


...do 


9 


15 


53 


...do 


Aug. 9 


Aug. 22 


12 


13 


112 


Aug. 9 


Aug. 15 


Aug. 26 


6 


11 


54 


July 29 


Aug. 3 


Aug. 16 


5 


13 


113 


...do 


Aug. 16 


Aug. 30 


7 


14 


55 


...do 


...do.... 


...do 


5 


13 


114 


Aug. 10 


Aug. 15 


Aug. 29 


5 


14 


56 


...do 


Aug. 4 


Aug. 17 


6 


13 


115 


Aug. 16 


Aug. 25 


Sept. 14 


9 


20 


57 


...do 


...do 


Aug. 18 


6 


14 


116 


...do.... 


...do.... 


...do 


9 


20 


58 


...do 


...do.... 


...do.... 


6 


14 


117 


...do.... 


Aug. 26 


...do 


10 


19 


59 


4a 


...do 


...do 


6 


14 














Average 








7.1 


13.6 


Mai 


ImiTm . , . 
















15 
3 


25 
9 


Min 


imum 



































THE CODLING MOTH IN MICHIGAN. 



17 



FIRST BROOD OF PUP^E OR SUMMER PUPJE. 

Time of pupation. — The time of pupation may be determined from 
the records of the pupal stage and the emergence of moths of the 
same brood (see fig. 11) since it is to be expected that the rate of 
pupation approximates that of the emergence of the moths resulting 
from these pupse. 

Table XIV. — Length of the pupal stage of the first brood, Douglas, Mich., 1910; sum- 
mary of Table XIII. 



Number 
(if obser- 
vations. 


Larvae in 
cocoon. 


Number 
of obser- 
vations. 


Pupal 

period. 


2 
11 
19 
15 
25 
17 
13 
7 
2 
4 
2 


Days. 
3 
4 
5 


8 

9 
10 

11 ' 
12 
15 


1 

2 • 


16 
38 
33 
11 

2 

1 

1 

1 

4 

1 


Days. 
9 
10 
11 
12 
13 
14 
15 
Hi 
17 
18 
19 
20 
25 



Length of pupal stage (Tables XIII and XIV). — The pupal stage 
of the first brood varied from 9 to 25 days with an average of 13.6 
days. The experiments of Table XIII include observations taken 
during the greater part of the pupal period. 

Table XV. — Time of emergence of moths of the summer brood from band-collected mate- 
rial of 1910. 



Date of 
emergence. 


Number of moths from band 
records at — 


New 
Rich- 
mond. 


Sauga- 
tuck. 


Lake 
Shore. 


Total. 


July 20 
July 27 
July 28 
July 29 
July 30 
July ;ii 
Aug. 1 
Au.:; 2 
An,-. :i 
Aug. 4 
Aug. 5 
Aug. 6 
Aug. 7 
Aug. 8 
Aug. 9 
Aug. 10 
Aug. 11 
Aug. 12 
Aug. 13 
Aug. 14 
Aug. 15 


2 
2 
4 

4 

4 

9 
2 
7 
4 
1 

11 
6 
12 
10 
3 
6 
6 
6 
8 
3 






2 
2 
10 
11 
8 
9 
28 
25 
25 
13 
8 
24 
13 
24 
23 
18 
12 
14 
18 
26 
25 






1 

2 
5 
16 
8 
3 
4 
5 
4 
4 
4 
9 
1 
1 

9 
5 




4 

14 

7 
10 
6 
3 
8 
3 
8 
9 
6 
5 
7 
5 
9 
17 



Date of 
emergence. 


Number of moths from band 
records at — 


New 
Rich- 
mond. 


Sauga- 
tuck. 


Lake 
Shore. 


Total. 


Aug. 10 
Aug. 17 
Aug. 18 
Aug. 19 
Aug. 20 
Aug. 21 
Aug. 22 
Aim. 23 
Aug. 24 
Aug. 25 
Aim. 26 
Aug. 27 
Aug. 28 
Aug. 29 
Aug. 30 
Aug. 31 
Sept. 1 
Sept. 7 
Sept. 8 


5 
3 
4 
2 
6 

8 
3 

2 

1 
1 
1 


14 
10 
3 
11 
9 
10 
21 
8 
6 
6 
5 

5 
1 
2 


12 
12 
13 
10 
10 
8 
28 
5 
9 
4 



5 
2 
1 


31 

25 

20 

23 

25 

18 

57 

10 

15 

10 

5 

8 

5 



5 

2 

1 

5 

1 


2 


3 
1 




Total.. 


153 


201 


202 


702 



18 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



FIRST BROOD OF MOTHS, OR SUMMER MOTHS. 

Time of emergence (fig. 7 arid-Table XV). — The records of emergence 
of the first brood of moths are from band-record material and should 
closely represent the actual time and rate of appearance of moths 
in the field. The larvae used in these experiments were from three 
separate band records (see Table XV), and the curve of figure 7 
represents the sum total of daily emergence from the combined 
sources. The first moth appeared July 26; a maximum of emergence 
occurred August 22, after which date only a few moths issued; the 
last moth of the brood emerged September 8. 

From the point of view of mechanical control the time of emergence 
of moths of the second brood of the codling: moth becomes of foremost 




Fig. 7. — Emergence curve of summer brood of moths in 1910, at Douglas, Mich. (Original.) 

importance, and this is one of the phases in the life history of the 
insect in which the literature on the codling moth is particularly 
deficient. This is mainly because of the difficult task of establishing 
accurate data, which at present involves carefully conducted band- 
record experiments. It is necessary that the bands be started in 
proper time and that the larvae be collected at regular and preferably 
at short intervals (three days) in order that the records on the 
emergence of moths may become fully reliable. 

Time of oviposition. — The so-called stock-jar experiments of Table 
XVI, including moths of the first brood, have been carried out under 
identically similar conditions as described on page 13 for the spring 
brood of moths. Egg deposition commenced from two to three 
days after the time of emergence of the moths, and extended on an 
average over a period of one week. In one instance eggs were laid 
18 days after the date of emergence of the moths. 



THE CODLING MOTH IN MICHIGAN. 



19 



Table XVI. — Egg deposition of the summer brood of moths in rearing cages, Douglas, 

Mkh., 1910. 



No. of 

experi- 
ment. 


Number 
of moths. 


Date of— 


Number of days— 


E mer- 
gence of 

moths. 


First ovi- 
position. 


Last ovi- 
position. 


Before 
first ovi- 
position. 


Of egg 
deposi- 
tion. 


From 
date of 

emer- 
gence to 
last ovi- 
position. 


1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 


10 
10 
21 i 
20 
30 
20 
27 
30 
10 
53 
11 


Aug. 11 
Aug. 12 
Aug. 14 
Aug. 16 
Aug. 17 
Aug. In 
Aug. 19 
Aug. 20 
Aug. 21 

Aug. 22 

Aug. 23 


Aug. 14 
Aug. 16 

...do 

Aug. 19 

...do.... 
Aug. 20 
Aug. 22 

...do.... 
Aug. 25 
Aug. 24 
Aug. 25 


Aug. 1!) 
Aug. 24 
Sept. 1 
Aug. 25 
...do.... 
Aim. 2(1 
Aug. 25 
Aug. 29 
Aug. 28 
Aug. 20 
Aug. 25 


3 
4 
2 
3 
2 
2 
3 
2 
4 
2 
2 



9 

17 
7 

7 

4 
8 
4 
3 
1 


8 
12 
18 
9 
8 
8 
6 
9 

4 
2 


Average 
Maximu 
Minimu 


m 

m 








2.0 
4 
2 


0.G 
17 
1 


8.2 
18 
2 



Egg deposition by individual moths. — Observations were taken on 
the egg deposition of six individual moths in captivity as given in 
Tables XVII, XVIII, and XIX. In most of these experiments pairs 
of male and female moths were used, which were removed from the 
stock jars before any oviposition had taken place. 

Table XVII. — Egg deposition by individual vioths of the summer brood, Douglas, Mich., 

1910. 



Date of 
egg 

deposi- 
tion. 


Number of individual moths. 


1 


2 


3 


4 


5 


6 


Date of emergence. 


July 28. 


Aug. 4. 


Aug. 10. 


Aug. 11. 


Aug. 14. 


Aug. 15. 


Aug. 5 
Aug. 7 
Aug. 8 
Aug. 9 
Aug. 10 
Aug. 11 
Aug. 12 
Aug. 13 
Aug. 15 
Aug. 16 
Aug. 17 
Aug. 18 
Aug. 19 
Aug. 20 
Aug. 21 
Aug. 22 


27 
6 

11 
6 
8 

10 

17 
6 






















36 
13 
22 
























































5 
4 

7 
2 






















1 
1 
3 
2 

4 




i 

1 












3 
6 
8 
















2 
3 




















Date of death of moths. 


Aug. 14 


Aug. 12. 


Aug. 25. 


Aug. 23. 


Aug. 24. 


Aug. 26. 



20 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



The moths of experiment No. 2 were found mating at 10.30 a. m., 
August 6, or two days previous to the first egg deposition. On an 
average the first eggs were laid five days after the emergence of the 
moths and for an average period of five days; the maximum number 
of eggs per female was 91; the average number of eggs per female, 
35.8. These figures are lower than those from similar but later 
experiments in 1911. 

Table XVIII.— Egg deposition by individual moths of the summer brood; summary oj 

Table X VII. 



Observations. 



Number of individual months. 



1 


2 


3 


4 


5 


91 


71 


18 


11 


17 


8 


4 


5 


6 


5 


9 


3 


4 


5 


3 


1 


2 


7 


2 


3 


17 


8 


IS 


12 


10 



Total eggs per female 

Days before egg deposition 

Days duration of egg deposition 
Days alive after egg deposition. 
Days moths lived 



Table XIX. — Egg deposition by individual moths of the summer brood; summary of 

Table XVII. 



Observations. 



Eggs per female 

Eggs per day per female 

Days before egg deposition per female 

Days of egg deposition per female 

Days moths lived after egg deposition 
Days moths lived 



Average. 


Maximum. 


35.8 


91 


7.16 


36 


5 


8 


5 


9 


3.18 


7 


12.1 


17 



Minimum. 



The moths were confined in common jelly glasses with perforated 
tin covers. A fresh pear leaf was inserted for egg deposition, and 
food was given in the form of dilute sugar and honey solution placed 
on a small piece of sponge. Most of the eggs were laid on the leaves, 
though a few were invariably also found on the glass. 

Judging from the records of emergence of moths and their habits as 
observed above, it becomes evident that the earliest eggs from this 
brood were laid about August 3. The height of the egg deposition 
period should have been September 1, and the close of the period 
September 15. 

Length of life of moths. — A record on the length of the life of the 
summer moths in the so-called stock jars was taken on 445 individuals 
(Tables XX and XXI). These moths were kept under similar con- 
ditions to those of the spring brood. 



THE CODLING MOTH IN MICHIGAN. 



21 



Table XX. — Length of life of moths of the first brood, in confinement, Douglas, Mich., 

1910. 



Number. 


Length 
of life. 


Number. 


Length 

of life. 


Number. 


Length 
of life. 


Number. 


Length 

of life. 


5 
15 
14 
34 
41 


Days. 
2 
3 
4 
5 
6 


70 
49 
56 
27 
23 


Days. 
1 
8 
9 
10 
11 


39 
27 
18 
5 
4 


Days. 
12 
13 
14 
15 
16 


9 
4 
2 
2 

1 


Days. 
17 
18 
19 
20 
24 



Total number of moths, 445. 

Table XXI.- — Length of life of moths of the first, brood in confinement, Douglas, Midi., 
1910; summary of Table XX. 



Observations. 


Length 
of life. 




Days. 
8.93 
24 
2 




Minimum 



The results of observations on the length of life for the two broods 
of moths are practically the same (compare Tables XI and XXI). 



LIFE CYCLE OF THE FIRST GENERATION. 

In the preceding pages the separate stages of the first generation 
have been considered at length, and the length of time of the devel- 
opment has been determined by a number of experiments for each 
stage. The final figures from these records thus represent the average 
life cycle of the codling moth of the first generation. 

Days. 

Incubation period of eggs 6 

Length of feeding of larvae 25 

Time of larvae in cocoons 7 

Length of pupal stage 13. 6 

Total 51.6 

To test the accuracy of the various experiments for the separate 
stages an additional experiment was undertaken in which a number 
of individual insects were carried through from the time of hatching 
to the emergence of the moths. 



22 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XXII.— Length of life cycle of the first generation, as determined by rearing in 

1910 at Douglas, Mich. 



03 

3 

-d 
V 

•3 
.3 
"3 
6 


Date of— 


Days — 


Egg dep- 
osition. 


Hatch- 
ing. 


Leaving 
the fruit. 


Pupa- 
tion. 


Emer- 
gence. 


a 

D 

a 

i— i 


Feeding of— 


a 

O o3 
O > 

o 

a 


0) 

u 

03 

"oB 
P, 
3 
Ph 


a 
"3 
>> 

o 

•2 

o 

Eh 


6 a" 

k > 

2. >-> 


bJD 

a . 


1 
o 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
20 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
40 
47 
48 
49 
50 
51 


June 25 
...do...... 

...do 

...do 


July 2 
...do 

...do 

...do 


July 26 
July 28 
July 29 
July 30 

...do 

July 31 
Aug. 1 
July 24 

...do 

July 26 
July 27 

...do 

...do 

July 28 
July 30 
July 23 
July 29 
July 30 
Aug. 1 
Aug. 2 

...do 

Aug. 3 
Aug. 4 
Aug. 6 

...do 


July 31 


Aug. 15 


7 

7 

7 

7 

7 

7 

7 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

7 

7 ' 

7 

7 

7 

7 

7 

7 

7 

7 

7 

7 

6 



6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 


24 

27 

28 
29 

20 
20 
22 
23 
23 
23 

17 

27 
27 

31 

25 
25 
25 

24 
26 

28 


26 
28 

30 

24 
20 

23 
24 
26 

28 
29 

31 
17 
20 

20 
27 
28 
29 
32 
30 
45 
23 

29 
33 
30 
30 
31 
31 
31 
33 
35 
35 


5 


15 


51 


Aug. 2 


Aug. 18 


4 


16 


54 


...do 

...do 

...do 

June 28 

...do 

...do..... 

...do 

...do 

...do 

...do 


...do 

...do 

...do 

July 4 

...do 

...do 

...do 

...do 

...do 

...do 


Aug. 8 
Aug. 9 


Aug. 23 
...do 


9 
9 


15 
14 


59 
59 


July 29 

...do 

July 31 
Aug. 2 

...do 

...do 


Aug. 13 

...do 

Aug. 16 
Aug. 18 
Aug. 20 
Aug. 15 


5 
5 
5 


6 


15 
15 
10 
10 
18 
13 


46 
46 
49 

51 
53 
48 


...do 


...do 












June 30 
...do 
...do 


...do 
July 6 
...do 


July 27 


Aug. 12 


4 


10 


43 












...do 


...do 












...do 

...do 

...do 


...do 

...do 

...do 


Aug. 6 
Aug. 12 


Aug. 20 
Aug. 24 


4 
10 


14 
12 


51 
55 


...do 


...do 












...do 

...do 

July 1 
...do 


...do 

...do 


Aug. 17 


Sept. 1 


11 


15 


63 


July 8 
...do 


July 25 
July 28 
Aug. 2 

...do 

...do 

Aug. 3 
Aug. 4 
Aug. 5 
Aug. 6 
Aug. 9 
Aug. 13 
Aug. 22 
Aug. 3 
Aug. 4 
Aug. 6 
Aug. 8 
Aug. 9 
Aug. 13 
Aug. 12 
...do 






















...do 

...do 

...do 

...do 

...do 


...do 

...do 

...do 

...do 
...do 


Aug. 4 
...do 

Aug. 9 


Aug. 18 
Aug. 19 
Aug. 23 


2 
2 

7 


14 
15 

14 


48 
49 
53 






...do 


...do 












...do 


...do 












...do 


...do 












...do 


...do 












...do 


...do 












July 5 

...do 

...do 

...do 

...do 

...do 


July 11 

...do 

...do 

...do 

...do 

...do 












Aug. 12 
Aug. 13 

...do 

...do 


Aug. 25 
Aug. 26 
Aug. 25 


8 

5 
4 


13 
13 
12 


51 
52 

51 






July 7 
...do 


July 13 
...do 






















...do 


...do 


Aug. 13 
...do 












...do 


...do 












...do 


...do 


...do 












..do 


...do 


Aug. 15 
Aug. 17 
...do 












..do 


...do 












..do 


...do 













Table XXIII.— Life cycle of the first generation; summary of Table XX LI. 





Incuba- 
tion. 


Feeding of— 


In cocoon 
as larva. 


Pupal 
stage. 


Total 
life cycle. 


Trans- 
forming 
larvse. 


Winter- 
ing 
larva?. 


Average 


Days. 
6.37 

7 
6 


Days. 
24.7 
31 
17 


Days. 
28.9 
45 


Days. 
6.0 
11 
2 


Days. 

14.5 

18 

12 


Dans. 
51.5 
63 
43 


Maximum 


Minimum 









The results of these experiments are given in Tables XXII and 
XXIII. Although limited in number the results of these experiments 
agree very closely with those of the previous experiments for the 
separate stages, namely, the life-cycle experiments averaged 51.5 days, 



THE CODLING MOTH IN MICHIGAN. 



23 



and the final average for the various experiments on separate stages 
averaged 51.6 days. 

The wintering larvte of the first brood, which complete their life 
cvcle the following spring, have not been included in the considera- 
tion of the life cycle of the first generation. 

THE SECOND GENERATION. 

SECOND BROOD OF EGGS. 

Length of incubation. — On an average the second brood of eggs 
(Tables XXIV and XXV) required 7.5 days for hatching, which is 
one day longer than was found necessary for those of the first brood. 
The maximum length of time for incubation was 11 days, the mini- 
mum 6 days. The red ring became first visible from three to four 
days after egg deposition and the black spot two days before hatching. 

Table XXIV. — Length, of incubation of the second brood of eggs laid in rearing cages, 

Douglas. Mich.. 1910. 



Xo. of 
obser- 
vation. 


Date of — 


Duration of— 


Egg Appear- 
ance ol 


Appear- 
ance of 


Batch- 


Red 


Black 


Incu- 


deposi- 
tion. 


red 


black 


ing. 


ring. 


spot. 


bation. 




ring. 


spot. 




















Days. 


Days. 


Days. 


1 


Aug. 2 


Aug. 5 


Aug. 10 


Aug. 12 


3 


s 


10 


2 


...do 


...do 


...do 


Aug. 13 


3 


S 


11 


3 


Aug. 3 


...do 


Aug. 9 


Aug. 11 


2 


ti 


8 


4 


Aug. 4 


Aug. 10 


Aug. 11 


Aug. 13 


ti 


7 


9 


5 


...do 


...do 


...do 


Aug. 14 


(i 


7 


10 


ti 


Aug. (i 
Aug. 7 






. .do.... 






8 


7 


Aug. 12 


Aug. 14 


Aug. 15 


5 


7 


8 


8 


..do 


...do 


...do 


Aug. 16 


5 


7 


9 


9 


Aug. 8 


Aug. 13 


...do 


Aug. 15 


5 


G 


7 


10 


...do 


...do 


...do 


Aug. 16 


5 


6 


8 


11 


Aug. 9 


Aug. 12 


...do 


...do 


3 


5 


7 


12 


...do 


...do 


...do 


Aug. 17 


3 


5 


8 


13 


Aug. 10 


Aug. 14 


Aug. lti 


...do 


4 


6 


7 


14 


Aug. n 


...do 


...do 


...do 


3 


5 


C> 


15 


...do 


...do 


...do 


Aug. 18 


3 


5 


7 


16 


Aug. 12 


Aug. 15 


Aug. 1, 


...do 


3 


5 


ti 


17 


...do 


...do 


...do 


Aug. 19 


3 


5 


7 


18 


Aug. 13 


Aug. lti 


Aug. 18 


.do... 


3 


5 


ti 


19 


...do 


...do 


...do 


Aug. 20 


3 


5 


7 


20 


Aug. M 


...do 


...do 


.do.... 


2 


4 


ti 


21 


Aug. 15 


Aug. 17 


Aug. 19 


Aug. 21 


2 


4 


H 


22 


...do 


..do 


...do 


Aug. 22 


2 


4 


7 


23 


Aug. li. 


Aug. 18 


Aug. 21 


...do 


2 


.") 


ti 


24 


. .do... 


.do 


...do 


Aug. 23 


2 


5 


7 


25 


Aug. 17 


Aug. 19 


...do 


.do.... 


2 


4 


ti 


26 


...do 


i,, 


...do.... 


Aug. 24 


2 


4 


7 


27 


Aug. IS 


Aug. 21 


Aug. 23 


...do 


3 


5 


ti 


28 


Aug. 19 


Aug. 22 


Aug. 24 


Aug. 25 


3 


5 


ti 


29 


Aug. 20 


Aug. 23 


Aug. 25 


Aug. 27 


3 


5 


7 


30 


Aug. 21 


...do 


...do.... 


...do 


2 


4 


ti 


31 


.do 


...do 


...do 


Aug. 28 


2 


4 


7 


32 


Aug. 22 


A tig. 25 


Aug. 27 


...do 


3 


5 


ti 


33 


...do 


...do.... 


...do 


Aug. 29 


3 


5 


7 


34 


A tin. 2:! 


Aug. 26 


Aug. 28 


...I.).... 


3 


5 


ti 


35 


...do 


...do 


...do 


Aug. 30 


3 


5 


7 


36 


Aug. 24 


Aug. 27 


Aug. 29 


. .do.... 


3 


5 


fi 


37 


...do 


...do 


.do... 


Aug. 31 


3 


5 


7 


38 


Aug. 25 


Aug. 29 


Aug. 31 


Sept. 2 


4 


ti 


S 


39 


.do... 


...do 


...do 


Sept. 3 


4 


(i 


9 


40 


Aug. 26 


Aug. 30 


Sept. 1 


.do 


4 


ti 


8 


41 


.do... 


...do 


.do 


Sept. i 


1 


6 


9 


42 


Aug. 28 


Sept. 2 


Sept. 4 


Sept. 5 


5 


7 


8 


43 


.do 


Sept. fi 


5 


7 


9 


44 


..do do 


'.'.'.do'.'.'.'.'. 


Sept. 7 


5 


7 


III 


45 


Aug. 29 Sept. 3 


Sept. 5 


Sept. 6 


.'» 


7 


v 


4<i 


..do <lo 


Sept. 7 


5 


7 


9 


Averace 


3. I 




7.4 


Ma\ii 




6 

2 


g 
4 


11 

6 


Mioin 


mm 



24: 



DECIDUOUS FEUIT INSECTS AND INSECTICIDES. 



Table XXV. — Incubation period of eggs of the second brood in rearing cages, Douglas, 
Mich., 1910; summary of Table XXIV. 



Appearance of 


Appearance of 


Total incubation 


red ring. 


black spot. 


period. 


Number 


Number 


Number 


Number 


Number 


Number 


of 


of obser- 


of 


of obser- 


of 


of obser- 


days. 


vations. 


days. 


vations. 


days. 


vations. 


2 


10 


4 


7 


6 


13 


3 


19 


5 


19 


7 


14 


4 


D 


6 


8 


8 


9 


5 


9 


7 


9 


9 


6 





2 


8 


2 


10 
11 


3 

1 











SECOND BROOD OF LARVAE. 



Time of Thatching. — The time of hatching of second-brood larvae 
under orchard conditions has been determined by methods described 
on page 14 for the first brood. A maximum abundance of newly 
hatched larvae occurred about September 10. The earliest larva of 
the brood hatched August 12. In the cages several late-deposited 
eggs failed to hatch, and it is possible that eggs in the field at this 
time would likewise remain undeveloped. 

Table XXVI. — Length of feeding of second-brood larvse, Douglas, Mich., 1910. 



a 


Date of— 




d 


Date of— 




d 


Date of — 










bi 








bi) 






bio 


"tg 






a 


+j 






a 


03 




a 


ID 




a; 


'■3 
1 


> 




J3 


'■3 









■3 




M 


+j 






bib 






& 


bib 






i-U 


1 


bfl+3 




£> 





M+J 







a 


bCiJ 




•2 


•S'3 





2. 


2 


.a 3 





"3 


3 


.S'3 





O 


o 


>*±; 










>£ 









t> £ 








03 


>, 








>> 








>> 


d 


03 


02 


03 


6 


03 




03 


d 


aS 




03 


£ 


w 


iJ 


ft 


£ 


w 


hJ 





fc 


w 


hJ 





1 


Aug. 15 


Sept. 12 


28 


28 


Aug. 19 


Oct. 1 


43 


55 


Aug. 24 


Oct. 1 


38 


2 


...do 


Sept. 13 


29 


29 


Aug. 20 


Sept. 24 


35 


56 


...do 


...do 


38 


3 


...do 


...do 


29 


30 


...do 


...do 


35 


57 


...do 


Oct. 2 


39 


4 


...do 


...do 


29 


31 


Aug. 21 


Sept. 15 


25 


58 


...do 


...do 


39 


5 


...do 


Sept. 15 


31 


32 


...do 


Sept. 20 


30 


59 


Aug. 25 


Sept. 15 


21 


6 


Aug. 17 


Sept. 20 


34 


33 


...do 


Sept. 21 


31 


60 


...do 


Sept. 27 


33 


7 


...do 


Sept. 24 


38 


34 


...do 


Sept. 22 


32 


61 


...do 


Oct. 1 


37 


8 


...do 


...do 


38 


35 


...do 


Sept. 23 


33 


62 


Aug. 26 


Oct. 2 


37 


9 


...do 


Oct. 1 


45 


36 


...do 


Sept. 24 


34 


63 


...do 


Oct. 3 


38 


10 


Aug. 18 


Sept. 23 


36 


37 


Aug. 22 


Sept. 12 


21 


64 


...do 


...do 


38 


11 


...do 


Sept. 24 


37 


38 


...do 


...do 


21 


65 


...do 


Oct. 7 


42 


12 


...do 


...do 


37 


39 


...do 


Sept. 23 


32 


66 


Aug. 28 


Sept. 24 


27 


13 


...do 


Sept. 28 


41 


40 


...do 


...do 


32 


67 


...do 


Oct. 3 


36 


14 


...do 


Oct. 1 


44 


41 


...do 


...do 


32 


68 


...do 


...do 


36 


15 


Aug. 19 


Sept. 12 


24 


42 


...do 


Sept. 26 


35 


69 


...do 


...do 


36 


16 


...do 


...do 


24 


43 


Aug. 23 


Sept. 23 


31 


71) 


...do 


Oct. 4 


37 


17 


...do 


Sept. 15 


27 


44 


...do 


...do 


31 


71 


...do 


...do 


37 


18 


...do 


27 


45 


...do 


Oct. 1 


39 


72 


...do 


Oct. 6 


39 


19 


...do 


Sept. '20 


32 


46 


...do 


...do 


39 


73 


...do 


...do 


39 


20 


...do 


...do 


32 


47 


...do 


Oct. 3 


41 


74 


Aug. 29 


Oct. 10 


42 


21 


...do 


...do 


32 


48 


Aug. 24 


Sept. 21 


28 


75 


Aug. 30 


Sept. 25 


26 


22 


...do 


Oct. 1 


43 


49 


...do 


Sept. 23 


30 


76 


...do 


Sept. 29 


30 


23 


...do 


...do 


43 


50 


...do 


...do 


30 


77 


Aug. 31 


Oct. 4 


34 


24 


.do 


...do 


43 


51 


...do 


Sept. 24 


31 


78 


...do 


Oct. 6 


36 


25 


...do 


...do 


43 


52 


...do 


Sept. 25 


32 


79 


...do 


...do 


36 


20 


...do 


...do 


43 


53 


...do 


...do.... 


32 


80 


Sept. 3 


Oct. 1 


2s 


27 


...do 


...do 


43 


54 


...do 


...do 


32 


81 


Sept. 4 


Oct. 6 


32 


Averasre 




34.2 


Ma 


ximum 






45 
21 


Mb 


limum 



























THE CODLING MOTH IN MICHIGAN. 25 

Table XXVII. — Feeding period of second-brood larvae; summary of Table XX VI. 



Number 


Davs 


Number 


Days 


Number 


Days 


of obser- 


of 


of obser- 


of 


of obser- 


of 


vations. 


feeding. 


vations. 


feeding. 


vations. 


feeding. 


3 


21 


5 


31 


G 


39 


2 


24 


11 


32 


2 


41 


1 


25 


2 


33 


2 


42 


1 


20 


3 


34 


7 


43 


3 


27 


3 


35 


1 


44 


3 


28 


C 


36 


1 


45 


3 

4 


29 
30 


6 

6 


37 
38 






81 


2,770 



Length of feeding period. — In Table XXVI will be found the records 
on the feeding periods for 81 individual larvae of the second brood. 
The average length of feeding for the total number of observations is 
34.2 days, the maximum 45 days, and the minimum L'l days. As is 
to be expected these results are much higher than those for the first 
brood (compare with Table XXIII), since at this time of year a much 
lower degree of temperature prevails, and more feeding may be neces- 
sary for the hibernating larvae. Figure 8 (p. 26) shows the jar used 
in the rearing of codling moth larvae. 

Time of leaving the fruit. — The Saugatuek band-record experiment 
of figure 10 shows that the earliest mature larva 1 appeared under the 
bands August 30, and that larvae were collected more or less abun- 
dantly throughout September and the early part of October. The 
almost total absence of larvae during November was to a large extent 
due to the scarcity of fruit, and this condition materially limited the 
number of second-brood larva*. 

Table XXVIII. — Band-record experiments, Saugatuek, Mich., 1910. 



~6 

M 

O 
O 

o 

o 
d 
'A 


Jj 

"o 

•5.9 
o 

'3 
A 


8 

c 

o 
d 


•5 

o 

So 

d 


1 

s . 
S3 

o 
d 

y 


o 

— - 

o- 1 
d 

y 


3 
1 . 

k. — 

a— i 

"3 
d 


"3 

\i 
u 

-- ■_ 


■a 

B 
o 
3 

a 

"3 
d 


CD 

3 

0) 

<a 


i 

— 
o 
d 


o 

So 

o— ' 
d 


1 
a . 

S3 

P. 3~- 

O 

d 


■5 
3 

a j 

d 


<§ . 

t- — 

3 
d 


"3 

t. „: 
i - 

"3 ? 


1 
o 

3 
4 
5 

7 
s 
S 
10 
11 
12 
13 
14 
15 
L6 
17 
IX 
19 
20 


July 13 
July 17 
July 20 
July 23 
July 26 
July 29 
Aug. 1 
Aug. 4 
Aug. 7 
Aug. io 
Aug. 13 
Aug. 16 
Aug. 19 
Aug. L'l> 
Aug. 25 
A.ug. 28 
Sept l 
Sept. 3 
Sept. 6 
Sept. 9 


1) 
41 
28 
34 
54 
35 
58 
54 
49 
27 
35 
32 
23 
35 
23 
14 
21 
8 
7 
17 


5 
34 
10 
19 
26 
21 
33 
30 
13 
8 
2 






1 
7 
17 
13 
20 
10 

s 

17 
1 

N 

8 
6 
7 

13 
3 
9 

3 

6 


21 
22 

23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 


Sept. 12 
Sept. 15 
Sept. 18 
Sept. 21 

Sept. L'l 

Sept. 27 

Sept. 30 
Oct. 3 

Oct. 6 
Oct. 9 
Oct. 12 
Oct. 15 
Oct. 18 
Oct. 21 
Oct. 24 
Oet. 28 
Oct. 30 
Nov. 2 

Total . 


13 

18 

19 

i 26 

10 

10 

7 
L'L' 

13 

3 

9 
11 
8 
5 
3 
2 

2 






11 
IS 
9 
6 
11 
6 
5 
19 
9 
1 
9 
5 
5 
3 
2 


1 
3 

3 

2 

1 
2 

1 

2 
1 


1 



i IS 
5 
3 

3 














i 

2 
1 
2 
1 

1 


i 
i 

5 

2 

3 

8 

18 

18 

25 

24 

17 

28 

9 

9 

11 

6 

7 


1 
1 

1 

1 

o 
I 
2 

4 






































II 






1) 










3 










1 










l 
2 



1 






































L'l 11 


8 










788 


313 


29 


237 







1 12 larvae escaped. 



26 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

BAND RECORDS OF 1910. 

The band-record experiments form a very important part in the 
study of the life history of the codling moth, and constitute at present 
the only safe test of the development of the insect under natural 




Fig. 8.— Cage used in determining feeding period of codling-moth larvae. (Original.) 

conditions. When carefully carried out these experiments furnish 
indispensable data on the relative abundance of the first and second 
broods of larvae, time of emergence of moths, parasitism, hibernation, 
etc. (see Table XXXI), and yield in addition an abundance of 
material for laboratory rearing experiments. 



THE CODLING MOTH IN MICHIGAN. 



27 



Table XXIX 


. — Lake Shore band-record experiments, Douglas, Mich., 


1910. 


•6 

u 

o 
5 

8 

3 

d 


3 

° ti 

3-9 
-2 

A 


8J 

u 

o 
d 


6 

o 

Ed 

d 


o 
d . 

S3 

O 

d 


£ 

o 

<~ 93 

0>-H 

o 


| . 

U _H 

CJ-H 

o 
d 


3 

- '— 
H-eJ 

2 -' 


■6 

o 
u 

s 

"3 
d 


o 
o 

"o-S 

a> 

a 


S3 

> 

u 
a 

o 
d 


o 
2 2 

O— ' 

d 


"3 
d 


o 

s_- 

>— OS 
OH 

d 

55 


1 • 

o 
d 


o 

0*0 


1 
2 
3 
4 
5 
6 
7 
8 
.9 
10 
11 
12 
13 
14 
15 

it; 

17 
18 
19 
20 
21 
22 


July 12 
Julv IS 
July 18 
July 21 
Julv 24 
Julv 27 
July 30 
Aug. 2 
Aug. 5 
Aug. 8 
Aug. 11 
Aug. 14 
Aug. 17 
Aug. 20 
Aug. 23 
Aug. 25 
Aug. 29 
Sept. 1 
Sept. 4 
Sept. 7 
Sept. in 
Sept. 13 


18 

30 
40 
31 
45 
75 
51 
42 
59 
59 
59 
66 
69 
50 
42 
40 
22 
27 
24 
11 
16 
1" 


17 
22 

28 
17 
27 
45 
35 
28 
25 
8 
9 
1 


1 








23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
3(1 
37 
38 
39 
40 
41 


Sept. 16 
Sept. 19 
Sept. 22 
Sept. 25 
Sept. 28 
Oct. 1 
Oct. 4 
Oct. 7 
Oct. 10 
Oct. 13 
Oct. 16 
Oct. 19 
Oct. 22 
Oct. 25 
Oct. 29 
Oct. 31 
Nov. 3 
Nov. 6 
Nov. 9 

Total . 


18 
15 
8 
14 
7 
9 
1 
5 

3 
1 
4 






8 
8 
3 
2 
2 
6 
1 
4 


1 
3 

3 

1 
1 


9 
4 
5 
9 
5 
2 



2 
1 
4 


2 

1 

2 

271 






8 

10 

10 

14 

18 

5 

2 

7 

25 

17 

20 

21 

12 

5 

15 

11 

8 

(i 

1 

4 

6 






2 

4 
4 
7 
2 
5 
4 
1 


























4 

8 

7 

22 

20 

29 

41 

40 

37 

36 

23 

11 

lfi 

15 

9 

9 

9 


1 

1 

1 
5 
4 
4 
2 
1 
1 
2 

3 
3 

1 
3 
4 






















1 










































2 


























1 


























2 

lis:, 














262 


30 


377 


45 













In 1910, band-record experiments were placed in three separate 
orchards, located several miles apart, for the purpose of establishing 
better average results and determining as far as possible the extent 
of existing variation in the time of development of the codling moth 
in the selected localities. These were chosen in regard to their rela- 
tive proximity to Lake Michigan, one near the lake, one 2 miles east, 
and the other 7 miles east of the lake. The influence of the lake upon 
the temperature over the fruit belt of the western part of Michigan 
is well known by the local fruit growers and horticulturists and is 
strikingly shown by the difference in the period of blossoming of 
apples. This period is much earlier in orchards situated inland and 
later in orchards near the lake. It should therefore be expected that 
the codling moth is influenced in its development to a similar extent. 

Table XXX. — Band-record experiment at New Richmond, Mich., in 1910; larvae col- 
lected by Mr. Herman Schultz. 



■6 
u 
o 

o 

E 

"3 

d 


Date of 
collect- 
ing. 


ai 
> 
a 

3 
6 
A 


c 

as 

— o> 

O-H 

d 

y 


ao 

"3 -A 
o 

d'3 
A 


j3 

3 

_ a 

O iH 

6 


- 
\- • 

3 « 


S '- 

- > 

- - 
-2, 

- § 

3~ 

.-3 

14 
26 

4(1 
18 
20 
19 
16 
8 
8 
2 
3 
4 
2 
1 
(I 


■6 

o 

- 

3 
d 

y 


Date of 
collect- 
ing. 


si 

> 

3 

d 

y 


GO 

A 

o 

as 

o — 

d 

A 


ad 

— r: 
O vT 


o . 

s- 

O -H 

d 


No. of para- 
sites, 1911. 

Total number 
of dead larvae. 


1 Julv 11 

2 Julv 14 


29 
55 
69 
57 
50 
50 
33 
38 
22 
15 
15 
15 
7 
5 
9 


12 

27 
20 
24 
21 
17 
9 
17 
3 
2 
1 


3 
2 
7 
4 
3 
8 
4 
1 




id 

17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 


Aug. 25 
Aug. 28 
Aug. 31 
Sept. 3 
Si'pt. (i 
Sept. 9 
Sept. 12 
Sept. 15 
Sept. 18 
Sept. 21 
Sept. 24 
Sept. 27 
Sept. 30 


■> 

8 

1 
9 

7 

10 
15 
10 
6 
3 
5 
1 




l 
6 
(i 
6 
3 
4 
5 
1 
3 
2 
2 
3 



1 

1 1 

1 

1 2 

4 

1 2 

5 



1 6 

2 2 
1 

1 1 

11) 207 






3 

4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 


Julv 17 
July 20 
Julv 23 
July 26 
July 29 
Aug. 1 
Aug. 4 
Aug. 7 
Aug. 10 
Aug. 13 
Aug. 16 
Aug. 19 
Aug. 22 


2 

11 
6 
6 
4 
11 
11 
10 
11 
11 
5 
4 
9 


1 
1 
































153 


32 






543 


137 







1 4 larva? escaped. 
35215°— Bull. 115, pt. 1—12 3 



28 



DKCIDUOUS FRUIT INSECTS AND INSECTICIDES. 



The three band records have been referred to as the Lake Shore 
experiments located near the shore of the lake southwest of Douglas ; 
the Saugatuck experiments, 2 miles from the lake and northeast of 
Saugatuck, and the New Richmond experiments, near the village of 
the same name, 7 miles from the lake. Of these the Saugatuck 
experiments represented closely the locality of the field station and 




Fig. 9. — Burlap bands on an apple tree, to catch codling-moth larvae. (Original. ) 

the results from these last band records have been used to supple- 
ment the laboratory rearing experiments. 1 Practically all of the 
apple trees used in these experiments were old and badly neglected, 
and none of the trees had for some time been sprayed with a poison 
spray, so that the codling moth had for years developed normally 
and unchecked in the above orchards. 

1 During 1909 and 1911 the band-record experiments, which in 1910 were interrupted on account of the 
absence of fruit during that season, were carried out in the orchard on the grounds of the station. 



THE CODLING MOTH IN MICHIGAN. 



29 



Whenever possible, winter varieties of apples have been used for 
the band records to test the extent of infestation of the second-brood 
larvae. This was not entirely possible in case of the Lake Shore and 
the New Richmond experiments because of the great scarcity of fruit 
during 1910, so that in these localities summer and fall varieties were 
used, in addition to winter varieties. The apple trees of the Sauga- 
tuck band experiments consisted of the following varieties: Three 
Baldwin trees, one Greening tree, two Golden Kusset trees, and one 
crabapple tree. Through the courtesy of Mr. Herman Schultz, of 
East Saugatuck, Mich., five of these trees were placed free of charge 
at the disposal of the station. 

The apple trees were prepared for the band experiment in the usual 
way. The loose and rough bark was scraped off from the trunk and 
main branches. Cracks and crevices and decayed hollows in the 
trees were plastered over with cement. A considerable amount of 
dead wood had to be removed from several of the trees before these 
could be used. A 4-ply burlap band about 5 inches wide was placed 
around the trunk of each tree and about 2 feet from the ground. 
Sometimes it was necessaiy to place additional bands around the 
main branches on badly damaged trees (fig. 9), but as a rule a single 
band was found to be sufficient. 

The bands were examined eveiy three days and the larvae collected 
from each orchard were brought to the laboratory for further obser- 
vations. The details pertaining to these records will be found in 
Tables XXVIII to XXXI. 



Table XXXI.— Summary of Lake Shore, Saugatuck, and New Richmond, Mich., band 

record experiments of 1910. 



Observations. 


Lake Shore. 


Saugatuck. 


New Richmond. 


Total. 


Per cent. 


Total. 


Per cent. 


Total. 


Per cent. 




985 

262 
377 
639 

75 
271 
860 

L ,,,_, 

598 
125 


100.0 

41.0 
59.0 
64.8 
7.6 
27. 5 
87.3 
3(1.5 
69. 5 
12.7 


78S 

201 
313 
514 
37 
Xil 
577 
201 
376 
211 


100.0 

25.5 
39.7 
65.2 
4.7 
30.1 
73.2 
:-!4. s 

65.2 

20. s 


543 

153 

137 
290 

42 
207 
479 
153 
326 

04 


100 


Moths emerging: 

1910 


28 2 


1911 


2"> 2 


1910-1911 


53 4 


Parasitized larvae 


7.7 

:ss l 




g8 2 


Transforming larva- of the first brood 


31.9 

Os 1 




] 1 s 







On examining the curves of figure 10, showing the results of the 
band experiments, it will be noted that the two broods of larvae 
overlap and can not be definitely determined from these experiments 
alone. With special reference to the Saugatuck experiments the 
hypothetical curves in figure 10 which have been drawn to repre- 
sent the two broods are based on the following considerations: The 



30 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



last moth of the spring brood emerged July 27; it required at that 
time of the season 45 days "from the date of emergence of the moth 
to time of maturity of the resulting larva. Thus the larva? of the 
first brood must have ceased to appear by September 10. The first 
moth of the first brood or summer moth emerged July 29, at which 
time the insect developed rapidly and mature larvae resulted in 33 




5 10 15 20 25 JO 5 

JULY 



10 I 

AUG 



5 20 2? 30 5 10 15 20 25 3 
UST SEPTEMBER 



5 10/5 20 25 30 f 10 
OCTOBER NOV. 



Fig. 10. — Curvos made from band-record experiments in orchards at the lake shore near Douglas, at 
Saugatuck, and at New Richmond, Mich., 1910. (Original.) 

days. Thus the first larvse of the second brood appeared August 31. 
Similarly, the first-brood and second-brood larvae in the Lake Shore 
and New Richmond experiments have been determined, with due 
consideration given to the seasonal conditions of each locality. 

The results from three band experiments may be appreciated by 
an examination of the curves in figure 10. A difference in the time 
and rate of maturity of larvae will be noted in considering the height 
of the curves representing the first brood. In the Lake Shore orchard 



THE CODLING MOTH IN MICHIGAN. 31 

the maximum occurred August 8, in the Saugutuck orchard July 31, 
and in the New Richmond orchard July 18. It will not be possible 
to compare the dates for the appearance of first larvae of the first 
brood, since the New Richmond experiments commenced slightly 
after the larvae began to appear. 

At the Lake Shore band experiments larvae were collected in great 
numbers during the month of August, whereas at New Richmond 
only a few were obtained. There is only a slight difference in the 
time of appearance of the earliest second-brood larva' in these locali- 
ties, winch would indicate the existence of a tendency on the part of 
the seasonal conditions to become equalized or uniform over the fruit 
belt at midsummer. At the Lake Shore orchard larva 1 continued to 
appear one month later than in the New Richmond orchard. Part of 
this difference was due to the scarcity of fruit at New Richmond, but 
also partly because of prevailing higher temperature during the fall 
near the lake, which prolonged the season in the latter locality. 1 
Though limited in scope, the results of these band experiments show 
that the codling moth varies in the time of its development in these 
three localities in close relation to existing climatic conditions, thus 
indicating that the insect must be governed by the same climatic con- 
ditions that govern the plants, and it must be due to this fact that 
we find a corresponding difference in the time of activity of the 
insect in the spring, as is noted in the time of blossoming of apples 
in the different sections of the fruit belt. 

Of the total number of larvse of the Saugatuck band experiment 
73.2 per cent pertained to the first brood and 26.8 per cent to the 
second brood. Of the first-brood larvae 34.8 per cent transformed 
the same season, and 65.2 per cent wintered in the larval stage. Of 
the total number of larva?, 25.5 per cent developed into moths in 
1910 and 39.7 per cent in 1911. Parasitism by Ascogaster carpo- 
capsse affected 4.7 per cent, and 30.1 per cent died during the winter, 
killed by cold. 

SUMMARY OF SEASONAL-HISTORY STUDIES OF 1910. 

Figure 11 represents graphically the main results of the seasonal- 
history studies of 1910 and can better be appreciated from the 
diagram than by description. 

Except for the prolonged pupal period during the very abnormal 
spring of 1910 the insect developed fairly normally so that from the 
point of view of the activities of the codling moth the season may 
be taken to have been about average. 

1 For a more thorough tost, records should be taken on temperature, time of blossoming of apples, and 
tin..' of emergence of spring brood of moths in the different sections in the fruit belt. 



32 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

SEASONAL-HISTORY STUDIES OF 1911. 

The results of the 1911 life-history studies of the codling moth are 
in many respects similar to those obtained during the previous year. 



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The main difference is that found in the time of transformation and 
date of appearance of the different stages, which is ascribed to the 
prevalence of a very unusually high temperature during the spring 



THE CODLING MOTH IN MICHIGAN. 



33 



and summer. To a certain extent the 1911 life-history studies con- 
stitute a test upon the 1910 investigation and in addition show the 
behavior of the codling moth under the above climatic conditions. 

In the presentation of the observations made during 1911 on the 
codling moth the same plan has been followed as for 1910, and many 
of the details concerning methods and tabulation previously described 
apply equally to the 1911 studies. 

Table XXXII. — Time of -pupation in the spring of 1911. 



Date of 


Number 


Date of 


Number 


Date of 


Number 


Date of 


Number 


pupa- 


of 


pupa- 


of 


pupa- 


of 


pupa- 


of 


tion. 


pupae. 


tion. 


pupa?. 


tion. 


pupa?. 


tion. 


pupa'. 


Mav 9 


1 


Mav 32 


10 


.Tunc 2 


2 


June 14 


3 


Mav 11 


1 


May 2,'} 


8 


June 3 


9 


June 1") 


1 


May 12 


1 


Mav 21 


8 


June 4 


3 


June 16 


1 


Mav 14 


(') 


Mav 25 


i 


June ."> 





June 17 


3 


Mav 15 


7 


Mav 2ti 


5 


June (i 


4 


June 19 


2 


Mav 16 


9 


Mav 27 


8 


June 7 


2 


June 21 


1 


Ma\ 17 


s 


Mav 28 


9 


June 8 


2 


June 22 


1 


Mav 18 


12 


Mav 29 


fi 


June 9 


7 


June 26 


1 


Mav 19 


1G 


Mav 30 


7 


June 10 


(1 






Mav 20 


14 


Mav 31 


11 


June 11 


4 






Mav 21 


11 


June 1 


3 


June 13 


1 







Total pupae, 212. 

SOURCE OF REARING MATERIAL. , 

The rearing material in the spring of 1911 consisted of wintering 
larvae, which in a normal way had entered hibernation the previous 
season. Practically all of the larvae were from band records and 
represented the normal proportion of both first-brood and second- 
brood larvae. The wintering cocoons were made between narrow 
strips of wood (fig. 4) and in pieces of corrugated paper (fig. 17). 
During the winter larvae were kept in an outdoor shelter. 



WINTER-KILLED LARV.E. 

The percentage of larvae killed by cold during the winter proved to 
be equally as high during 1911 as observed in 1910. After the com- 
pletion of the different band-record observations the results show the 
following percentages of winter-killed larvae: 

Per cent. 

New Richmond band records 38. 1 

Saugatuck band records 30 

Lake Shore band records 27. 5 

From these figures should be substracted a small number of larvae 
injured in the course of transportation from the field to the laboratory. 
Those from New Richmond showing the liighest percentage of mor- 
tality were sent in boxes through the mail and suffered more or less 
under transportation. 1 The larvae from the Lake Shore and Sauga- 

1 During 1911 an improvement was made in the method of shipping the larvae from the distant 
localities of the band records, by the use of mailing tubes (see page 61 and fig. 17). 



34 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



tuck orchards, however, were all carefully handled, and the results 
of these observations show approximately the normal proportion of 
winter-killed larvae. 

SPRING BROOD OF PUP^. 

Time of pupation. — In the rearing cages pupation commenced on 
May 9, reached a maximum May 19, and terminated June 26 (Table 
XXXII). The relative rate of pupation is illustrated by a curve in 
figure 12. It will here be observed that pupation occurred rather 
irregularly and that the time when the larger number of individuals 
pupated extended over a longer period than in 1910. This, of course, 
had a direct bearing upon the time and rate of emergence of the 
moths of the spring brood, which, . like the pupae, appeared very 
irregularly. 

Table XXXIII. — Length of pupal stages of the spring brood, Douglas, Mich., 1911. 



No. 


Pupated. 


Emerged. 


Days. 


No. 


Pupated. 


Emerged. 


Days. 


No. 


Pupated. 


Emerged. 


Days. 


1 


May 14 


Mav 29 


15 


42 


May 21 


June 10 


20 


83 


May 29 


June 19 


21 


2 


...do 


...do 


15 


43 


...do 


June 9 


19 


84 


...do do 


21 


3 


...do 


May 30 


16 


44 


...do 


June 10 


20 


85 


May 30 June 20 


21 


4 


May 15 


May 28 


13 


45 


May 22 


June 14 


23 


86 


...do ' June 18 


19 


5 


...do 


May 3J 


15 


46 


...do 


June 11 


20 


87 


...do June 19 


20 


C 


May 10 


...do 


14 


47 


...do 


June 10 


19 


88 


May 31 June 21 


21 


7 


...do 


June 


21 


48 


...do 


June 9 


18 


89 


...do do 


21 


8 


Mav 17 


June 2 


16 


49 


...do 


June 10 


19 


90 


.. .do June 20 


20 


9 


...do 


.June 3 


17 


50 


May 23 


...do 


18 


91 


...do June 19 


19 


10 


...do 


...do 


17 


51 


...do 


...do 


18 


92 


. . .do June 20 


20 


11 


...do 


June 10 


24 


52 


...do 


June 1 1 


19 


93 


June 1 ...do 


19 


12 


...do 


June 2 


16 


53 


...do 


June 10 


18 


94 


June 2 


June 22 


20 


13 


May 18 


June 3 


16 


54 


Mav 24 


June 


13 


95 


...do 


June 21 


19 


14 


...do 


...do 


16 


55 


...do 


June 9 


16 


96 


June 3 


June 22 


19 


15 


...do 


June 6 


19 


56 


...do 


June 10 


17 


97 


...do 


June 21 


18 


10 


...do 


June 4 


17 


57 


...do 


June 11 


18 


98 


June 4 


June 23 


19 


17 


...do 


June 5 


18 


58 


...do 


June 14 


21 


99 


...do 


June 24 


20 


18 


...do 


June 4 


17 


59 


...do 


June 11 


18 


100 


June 5 


June 23 


18 


19 


...do 


June 5 


18 


60 


May 25 


June 12 


18 


101 


...do 


...do 


18 


20 


May 19 


June 6 


18 


61 


...do 


June 14 


20 


102 


...do 


June 24 


19 


21 


...do 


June 5 


17 


02 


...do 


...do 


20 


103 


...do 


...do 


19 


22 


...do 


...do 


17 


03 


...do 


June 12 


18 


104 


June 6 


June 23 


17 


23 


...do 


...do 


17 


04 


...do 


June 14 


20 


105 


...do 


June 24 


18 


24 


...do 


...do 


17 


05 


...do.... 


June 12 


18 


106 


June 8 


...do 


16 


25 


...do 


June 


18 


60 


May 20 


June 10 


21 


107 


June 9 


June 25 


16 


20 


...do 


June 4 


16 


67 


...do 


June 15 


20 


108 


...do 


June 27 


18 


27 


...do 


June 5 


17 


68 


...do 


June 14 


19 


109 


...do 


June 20 


17 


28 


...do 


Jime 6 


18 


69 


...do 


...do 


19 


110 


...do 


...do 


17 


29 


...do 


June 4 


16 


70 


Mav 27 


June 15 


19 


111 


June 10 


...do 


16 


30 


...do 


June 7 


19 


71 


...do 


June 10 


20 


112 


...do 


June 27 


17 


31 


...do 


June 6 


18 


72 


...do 


June 19 


23 


113 


...do 


...do 


17 


32 


Mav 20 


June 9 


20 


73 


...do 


June 15 


19 


114 


...do 


...do 


17 


33 


...do 


June 8 


19 


74 


...do 


June 10 


20 


115 


June 11 


June 30 


19 


34 


...do 


June 9 


20 


75 


Mav 28 


June 18 


21 


110 


June 13 


...do 


17 


35 


...do 


June 8 


19 


76 


...do 


...do 


21 


117 


June 14 


...do 


16 


36 


...do 


June 7 


18 


77 


...do 


...do 


21 


118 


...do 


July 8 


24 


37 


...do 


June 8 


19 


78 


...do 


...do 


21 


119 


June 15 


July 2 


17 


38 


...do 


...do 


19 


79 


...do 


June 17 


20 


120 


June 17 


June 30 


13 


39 


Mav 21 


June 10 


20 


80 


...do 


June 18 


21 


121 


...do 


July 2 


15 


40 


...do 

...do 


June 8 
June 10 


18 

20 


81 
82 


Mav 29 
...do 


...do 

June 19 


20 

21 


122 


June 21 


July ."> 


14 


41 


























18.41 




24 






















13 























THE CODLING MOTH IN MICHIGAN. 



35 



Length of pupal stage. — Owing to the very variable climatic condi- 
tions during the pupal period there resulted a considerable difference 
in the length of the pupal stage. The observations for the spring 
brood extended from May 14 to July 8, during which time records 
were taken from 122 individual insects. 

Table XXXIV. — Length of pupal stages of the spring brood; summary of Table XXXIII. 



Number 
of obser- 
vations. 


Pupal 
period. 


Number 
of obser- 
vations. 


Pupal 
period. 


Number 
of obser- 
vations. 


Pupal 
period. 


3 
2 
4 

12 


Days. 
13 
14 
15 
16 


18 
22 
23 
20 


Days. 
17 
18 
19 
20 


14 
2 
2 


Days. 

21 
23 

24 




Fig. 12. — Curve of spring pupation of the codling moth in 1911 , at Douglas, Mich. (Original.) 

The results are given in Table XXXIII and are further summa- 
rized in Table XXXIV. The average length of the pupal stage was 
18.4 days, the minimum length 13 days, and the maximum 24 days. 

Relation of temperature to the duration of the pupal stage. — From 
general observations it has long been known that the temperature 
has a marked effect upon the duration of the pupal stage. The 
intimacy of this relation has already been pointed out by different 
investigators and most recently by Prof. E. D. Sanderson in a paper 
on the relation of temperature to the growth of insects. 1 

In our tentative effort to find the existing relation of the tempera- 
ture to the length of the pupal period at Douglas, Mich., the average 
temperature has been taken from the average daily temperature 



i Journ. Econ. Ent., Ill, p. 113, 1910. 



36 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



during the pupal stage of a number of individual insects. These 
averages were computed from the temperature records of Table 
LXX, which are from a self-recording thermometer of the type 
used by the United States Weather Bureau. The instrument was 
regulated in accordance with a mercury thermometer and was kept 
in the rearing shelter throughout the season. The records in Table 
XXXIII give the date of pupation and the date of emergence of 
moths for 122 individual insects. 




Fig. 13. — Curve showing relation of temperature to the duration of the pupal stage in the spring brood of 
the codling moth; Douglas, Mich., 1911 (from Table XXXV). (Original.) 

Table XXXV. — Average daily temperature during the pupal periods of the spring 
broods; summary of Table XXXIII. 



Pupal 
period. 

Day.':. 
13 
14 
15 
lfi 
17 
18 


No. of 
obser- 
vations. 


Average mean temperature. 


Pupal 
period. 


No. of 
obser- 
vations. 


Average mean temperature. 


Average. 


Maxi- 
mum. 


Mini- 
mum. 


Average. 


Maxi- 
mum. 


Mini- 
mum. 


3 

2 
4 
12 
18 
22 


F. 
68.31 

71.41 
69.19 
67.29 
67.32 
66.50 


° F. 

69.86 

73.77 

70.08 

68.56 

69.29 

68.23 


° F. 

66.02 

69.06 

68.83 

65. 51 

66.06 

65.26 


Day*. 
19 
20 
21 
23 
24 


23 
20 
14 
2 
2 


° F. 

65.84 

65.65 

65.01 

65 33 

69.52 


° F. 

67.29 

66.81 

67.58 

65. 61 

71.73 


° F. 

64.48 

64.53 

64.49 

65. 05 

67.32 



Observations on the time of transformation were made once daily 
and invariably in the afternoon. In Table XXXV a summary of 
these temperature records is given showing the averages for each day 
and also the number of individual pupse under observation for the 



THE CODLING MOTH IN MICHIGAN. 



37 



respective days. To show the extent of variation in results obtained, 
the maximum and minimum of average temperatures of individual 
pupal stages are given for the different days in the same table. On 
examining the diagram of figure 13 it will be noted that where the 
averages have been made from a large number of observations the 
results are fairly uniform. These results here show a marked de- 
crease in the time of the pupal stage with an increase of temper- 
ature. Considering the curve of this figure we get the following 
readings : 

°F °C 

For the 15 days pupal stage 09.2 or 20.6 

F< >r the 17 days pupal stage 67.3 or 19.6 

For the 19 days pupal stage 66.0 or 18.9 

For the 21 days pupal stage 65.1 or 18.4 

It should be remembered that besides the temperature there are 
other factors affecting the development of the insects. Moisture 
and the physical condition of individual insects, etc., naturally tend 
to cause variation in the length of the pupal stage, and to these 
factors may be ascribed certain variations in the results obtained. 

SPRING BROOD OF MOTHS. 

Time of emergence of moths. — The earliest moths, emerging May 26, 
were about normal in the date of appearance. Subsequently, how- 
ever, and for the rest of the emergence period, the moths appeared 
very irregularly and for a longer period than usual. At the height of 
the emergence, during the middle part of June, two fairly long delays 
were caused by prevailing rains and a drop of temperature, so that 
the emergence period, as shown in figure 14, became marked by two 
distinct maximums. The records for the emergence of 1,127 moths 
are given in Table XXXVI. The first moth of the summer brood 
emerged July 7 and the last moth of the spring brood emerged July 
8, thus causing the emergence periods of the two broods to overlap. 



Table XXXVI. — Time of emergence of moths of the spring brood, Douglas, Mich., 1911, 





Total 


Date of 


Total 


Date of 


Total 


Date of 


Tot al 


















emergence. 


gence. 


emergence. 


gence. 


emergence. 


gence. 


emergence. 


gence. 


May 25 




June 6 


47 


June 18 


44 


June 30 


16 


May 26 


1 


June 7 


30 


June 19 


53 


July 1 


7 


May 27 


11 


June S 


68 


June 20 


44 


July 2 


7 


May 28 


6 


June 9 


52 


June 21 


41 


July 3 


2 


May 29 


19 


June 10 


62 


June 22 


54 


July 4 


1 


May 30 


12 


June 11 


35 


June 23 


56 


July 5 


10 


May 31 


10 


June 12 


20 


June 24 


45 


July 6 




June 1 


3 


June 13 


2 


June 25 


23 


July 7 




June 2 


29 


June 14 


48 


June 26 


37 


July S 


1 


June 3 


49 


June L5 


20 


June 27 


22 






June 4 


49 


June 10 


16 


June 28 


4 






June 5 


43 


June 17 


15 


June 29 


13 







Total, 1,127 moths. 



38 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Egg deposition by individual moths. — Already during 1910 several 
experiments had been made to-determine the number of eggs deposited 
by a single female. The results from these observations were, how- 
ever, limited to a few females and could not be considered conclusive. 
Further efforts were therefore made in 1911 to obtain additional data 
on this question. Many difficulties have been encountered in getting 
moths that will oviposit in captivity. The obstacles have probably 




Fig. 14. — Emergence curve of moths of the spring brood in 1911, at Douglas, Mich. (Original.) 

been due to the fact that mating had not taken place, it being difficult 
to find the insects in copulation or to bring about mating by confining 
together single pairs of male and female moths. In the stock-jar 
cages, where a number of male and female insects have been confined, 
eggs have always resulted in abundance and mating must have occurred 
quite generally though it was only observed on rare occasions. It 
was therefore planned to remove female moths from the stock jars 
after the moths had been confined together two or three days, and 
prior to any egg deposition in the stock jars. 



THE CODLING MOTH IN MICHIGAN. 



39 



Table XXXVII. — Egg deposition in confinement by individual moths of the spring 
brood, Douglas, Mich., 1911. 



Date of 
egg depo- 
sition. 


Number of individual moths. 


1 


2 


3 


4 


5 





7 8 


9 Hi 


11 


12 


Date of emergence of moths. 




a) 

§ 


■■a 

| 


5 


o 


Pi 

I 


~i 

o 
| 


o 

l-a 


2 


J 


CD 

a 

3 


IN 
CD 

3 
3 


June 10 
June 11 
June 12 
June 13 
June 14 
June 15 
June 16 
June 17 
June 18 
June 19 
June 20 
June 21 
June 22 
June 23 
June 24 
June 25 
June 26 
June 27 
June 28 
Jime 29 
Jime 30 
July l 
Julv 2 
Julv 3 
Julv 4 
July 5 






20 


















1 


ii 














































































































































I 
8 

20 


33 

4 

37 

35 

3 

14 

35 
















1(1 
2 
2 

20 
8 

14 




















24 


































































































ti 
26 












10 
3 
















































































17 

56 
13 
15 
1 
















28 

4 
3 




68 

28 


2 

7 

40 






' 




















1 

14 
















































5 
33 












































Dale of death of moths. 


3 
Ha 




June 10. 

0) 


i 


3 


5 

f-a 


so 

3 


| 


jg 


SO 

3 


00 

3 



1 Escaped June 20. 

In all 160 female moths were removed from the different stock jars 
(Table XL) and were kept isolated in glass tumblers, covered with 
perforated tin covers. A small piece of sponge dipped in diluted 
sugar-and-honey solution was inserted to supply food. To encourage 
egg deposition fresh pear leaves were placed in the tumblers and were 
daily replaced by fresh foliage at the time the tumblers were examined 
for eggs. 

Table XXXVIII. — Egg deposition by individual moths; summary of Table XXXVII. 



Observations. 








Number of individual moths. 








1 


_> 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


Total eggs per female 

Days before egg deposition . 

Days duration of egg 


70 
7 

16 

5 
27 


35 

9 

2 

17 


26 
4 

1 



4 


36 

ii 

4 


101 
6 

2 
14 


35 
9 

3 

1 
12 


32 

4 

2 
3 


SI, 

5 
2 

s 


102 

4 

6 

3 
L2 


49 
3 

3 

10 


15 
5 

2 

4 
10 


38 
8 

2 


Days alive after egg depo- 


3 




8 U 


12 















40 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XXXIX. — Egg deposition by individual moths; summary of Tables XXXVII 

and XXXVIII. 



Observations. 



Average. 


Maximum. 


57.08 


161 


16.31 


58 


5.60 


9 


4.75 


16 


3.27 


8 


12.72 


27 



Minimum. 



Eggs per female 

Eggs per day per female 

Days before' egg deposition per female 

Days of egg deposition per female 

Days moths lived after egg deposition 
Days moths 1 ived 



From the 160 separate experiments only 12 yielded results worth 
recording, and these are given in Tables XXXVII-XXXIX. The 
following observations are recorded in Table XXXVII: The time of 
emergence of the different moths, the time and amount of egg depo- 
sition per female, and the date of death of each of the female moths. 
In Table XXXVIII a summary of results will be found showing the 
number of eggs per female, the number of days before egg deposition, 
the duration of egg deposition, and the length of life of the moths. 
It will be noted that on an average these "moths commenced to oviposit 
5.6 days after their emergence; the maximum length of this period 
was 9 days and the minimum 3 days. Egg deposition extended on 
an average over a period of 5 days. The average number of eggs per 
female was 57.08, the maximum number of eggs per female 161, and 
the minimum 15 eggs per female. The moths lived, on an average, 
3.2 days after egg deposition; in one instance death followed the day 
after the last oviposition ; on the other extreme a single moth lived 8 
days after the last egg deposition. 

The conditions under which it was necessary to keep these moths 
for observation were of course quite abnormal and it is doubtful 
whether all of the moths deposited the normal number of eggs. It is 
the writer's opinion that in the field the average number of eggs per 
female is considerably higher and may reach an average of 75 to 85 
eggs per female. 

Egg deposition in stock-jar experiments. — The nature of the stock- 
jar tests has already been described on page 13. As will be found in 
Table XL, the observations merely cover the date of emergence of 
moths in each cage and the date of the first and last egg depositions 
per jar, which give only an idea of the extent of the oviposition 
period. We find from these data that on an average the first eggs 
were laid four days after the date of emergence of the moths. 



THE CODLING MOTH IN MICHIGAN. 



41 



Table XL. — Oviposition by moths of the spring brood in rearing cages, Douglas, Mich., 

1911. 



Cage 
No. 


Num- 


Date of— 


Number of days — 












From 


ber of 
moths. 


Emer- 
gence of 


First 
ovi- 


Last 
ovi- 


Before 

ovi- 


Duration 
of ovi- 


date of 
emer- 
gence to 
last ovi- 






moths. 


position. 


position. 


position. 


position. 
















position. 


1 


13 


May 24 


May 28 


June 14 


4 


is 


21 


2 


20 


Mav 29 


June 3 


June 21 


5 


19 


23 


3 


9 


May 30 


June 10 


June 10 


11 


1 


11 


4 


10 


May 31 


June 6 


June 8 


6 


3 


8 


5 


5 


June 1 


...do 


June 9 


5 


4 


8 


6 


29 


June 2 


...do 


...do 


4 


4 


7 


7 


39 


June 3 


June 5 


June 21 


2 


17 


18 


8 


47 


June 4 


J une 8 


June 20 


4 


13 


16 


9 


40 


June 5 


June 9 


June 9 


4 


1 


4 


10 


43 


June ti 


...do 


June 24 


3 


16 


IS 


11 


29 


June 7 


June 10 


June 20 


3 


11 


13 


12 


56 


June 8 


June 11 


June 23 


3 


13 


15 


13 


45 


June 9 


June 12 


June 15 


3 


4 


6 


14 


50 


June 10 


June 13 


June 22 


3 


II) 


12 


15 


14 


June 17 


June 22 


June 2ti 


5 


5 


9 


16 


48 


June 19 


June 23 


June 27 


4 


5 


8 


17 


38 


June 23 


June 25 


...do 


2 


3 


4 


18 


44 


June 24 


June 27 


June 30 


3 


4 


6 


19 16 

Average 


June 25 


...do 


July 2 


2 


6 


7 




4 


8.3 


11.3 


Maxin 


ium 






11 
2 


19 
1 


23 
4 


Miniir 


urn 















The shortest period before first egg deposition was 2 days, and the 
maximum period 11 days. Within the separate cages oviposition 
lasted from 1 to 19 days, with an average of 8.3 days. When we 
consider the period from the date of emergence to the date of last 
oviposition we find a maximum length of time of 23 days, an average 
of 11.3 days, and a minimum of 4 days. 

Period of egg deposition.— In the field egg deposition is estimated 
to have taken place from May 28 to July 18, with a maximum number 
of eggs between June 10 and June 30. This has been estimated from 
the records of egg deposition by moths in captivity, the time of emer- 
gence of the moths, and the band-record observations. 

Length of life of moths. — The length of life of 153 male and 177 
female moths, confined in the stock jars, is given in Table XLI. On 
an average the males lived 9.18 days and the females 10.63 days. 
The maximum length of life for the males was 18 days and for the 
females 23 days. 



42 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XLI. — Length of life of male and female moths of the spring brood in captivity; 
summary of records of 330 individual moths, Douglas, Mich., 1911. 



Male. 


Female. 


Male. 


Female. 


Length 


Number 


Length 


Number 


Length 


Number 


Length 


Number 


of life. 


of moths. 


of life. 


of moths. 


of life. 


of moths. 


of life. 


of moths. 


Days. 




Days. 




Days. 




Days. 




2 


2 


2 


2 


14 


11 


14 


9 


3 


2 


3 


4 


15 


8 


15 


13 


4 


12 


4 


6 


10 


3 


16 


5 


5 


11 


5 


5 


17 


2 


17 


5 


6 


11 


(i 


10 


18 


1 


18 


7 


7 


14 




13 






19 


4 


8 


18 


8 


18 






20 


2 


9 


15 


9 


20 






21 


1 


10 


16 


10 


22 






23 


1 


11 


11 


11 


13 














12 


15 


12 


14 




153 




177 


13 


1 


13 


3 











Table XLII. — Length of life of male and emale moths of the spring brood in captivity, 
Douglas, Mich., 1911; summary of Table XLI. 



Observations. 


Life of 

male 

moths. 


Life of 
female 
moths. 




Dai/s. j Days. 
9. 18 10. 03 
18 23 
2 2 













It is of interest to note that in this brood, as well as in the summer 
brood, the females were more numerous than the males and survived 
the males on an average by about two days. 



THE FIRST GENERATION 



FIRST BROOD OP EGGS. 



Length of incubation. — Observations on the length of incubation 
extended over the greatest period when eggs occurred in the field 
(Table XLIII). The high temperature which at times prevailed 
brought the minimum length of incubation down to 4 days, against 
6 days for the same brood in 1910. The average length of incubation 
for the brood was 8 days, the maximum 10 days. Observations on 
the embryological development of the eggs were also taken as recorded 
in Table XLIII. The so-called "red ring" generally appeared 3 
days after egg deposition, and the "black spot" 2 days previous to 
hatching. 



THE CODLING MOTH IN MICHIGAN. 



43 



Table XLIII. — Length of incubation of the first brood of eggs and average mean tempera- 
ture during incubation, Douglas, Mich., 1911. 



No. of 
obser- 


No. of 


vation. 


eggs. 


1 




2 




3 




4 




5 




6 




S 


14 


9 


81 


10 


15 


11 


146 


12 


15 


13 


68 


11 


20 


15 


50 


Hi 


8 


17 


31 


is 


46 


111 


13 


20 


51 


21 


18 


22 


60 


23 


18 


24 




2.5 


48 


26 


66 


27 


17 


28 


47 


29 


18 


30 


28 


31 


10 


32 


52 


33 


82 


34 


24 


35 


7 


36 


34 



Date- 



Depos- 
ited. 



May 28 
May 30 
June 
June 
June 
June 
June 
June 
June 
...do.... 
June 10 
...do.... 
June 11 
...do.... 
June 12 
...do.... 
June 13 
June 11 
...do.... 
June 15 
...do.... 
June 16 
..do.... 
June Is 
June 19 
June 20 
...do..... 
June 21 
June 22 
June 24 
June 26 
...do.... 
June 27 
June 28 
June 29 
Julv 2 



Red 

ring. 



June 1 

June 3 

June 4 

June 7 

June 6 

June 8 



Black 

spot. 



Tune "i 
June 8 

..do 

June II 
June lo 



June 11 
June 12 
..<l.i.... 
June 13 

.do.... 
June 14 
...do.... 
June 15 
..do.... 
June 16 
June is 

.do.... 
June 19 

.do. 
June 20 

.do.... 
June 21 
June 22 
..do.... 
..do.... 
June 24 
June 25 
June 27 
June 29 
..do.... 



June 15 

June lii 
...do 



July 

July 



July 4 



June 18 

.do 

June 19 

...do 

June 20 
June 21 

..do 

..do 

...do 

June 22 

..do 

June 23 
June 24 

..do 

June 2.5 
June 26 
June 27 
June 30 
July 1 

..do 

Julv 3 

..do 

Julv 4 
Julv 5 



Hatched. 



June 
June 
June 
June 
June 
June 
June 
June 
...do. 
June 
June 
June 
..do 
June 

.do. 
June 

.do. 
..do. 
June 

.do. 
June 
June 
June 
..do. 
June 
June 
June 
June 
June 
July 
July 
July 
Julv 
..do. 
Julv 
July 



Duration of— 



Red 
ring. 



Days 

4 
4 
3 
3 
3 
3 



Black 
spol . 



Incu- 
ba- 
tion. 



Days. 

s 
9 

7 



Days. 

10 
10 



Average 
mean 

temper- 
ature. 



F.° 

64.27 
64.21 
65. 79 

67.78 
67.87 
66.38 
65.07 
65.27 
65.30 
64.96 
63.68 

61. 12 

62. 93 

63. 58 
63.29 

63.97 
61. 50 
65.21 

uu. 55 

67. IS 
68 30 
67. 73 
68.93 

70.95 

72. 10 

73. OS 

72. 52 

73. 67 
73.42 
69.15 
70.07 
71.61 
72.51 
7:i. 16 
76. 96 
S2.S0 



Table XLIV. — Incubation periods of first-brood eggs; summary of Tabic XLIII. 



Appearance of red 
ring. 


Appearance of 
black spot. 


Total incubation 
period. 


Number 

of days. 


Number 
of obser- 
vations. 


Number 

of days. 


Number 
vat ions. 


Number 
of days. 


Number 
of obser- 
vations. 


2 
3 
4 


3 
21 
10 


3 
1 

S 
6 

7 
s 
9 


1 
1 
8 
6 
13 
1 
1 


4 
6 

7 
8 
9 
10 


1 
6 
6 
8 
10 
5 























35215°— Bull. 115, pt 1—12- 



44 



MXIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XLV. — Incubation periods of first-brood eggs; summary of Tables X LIU and 

XLIV. 



Observations. 


Number of days — 


For appear- 
ance of 
red riii;,'. 


For appear- 
ance of 
black spot. 


For incu- 
bation. 




3. 206 

4 
2 


6.161 

9 
3 


7.944 
10 
4 




Minimum 



Table XLYI. 



. I oerage mean temperature during incubation of first brood of eggs, 1911; 
summary of Table XLIII. 



Number 

of ob- 
serva- 
tions. 


Days of 
incuba- 
tion. 


Average mean temperature. 


Average. 


Maximum. 


Minimum. 


1 
6 
6 
8 
10 
5 


4 
6 

8 
9 
10 


°F. 

82.80 

73.04 

71.03 

67.65 

65. 03 

64.03 


"F. 


°F. 


76. 96 

73. 08 
72.52 
68.30 
64.27 


70.07 
67. 73 
65. 21 
62. 93 
63.58 



Effect of temperature upon time of incubation. — One of the greatest 
factors affecting the time of incubation is the temperature. This is 
fully shown from the results of the temperature records for the time 
of incubation both for the first and second broods of eggs as brought 
out in the curve of figure 15. 

Because of the similarity of results obtained, the two broods of 
eggs are here considered together. The same methods of computing 
results have been followed as for the spring brood of pupae (p. 10). 
In Tables XLIII and LVII the average mean temperature is given 
for the time of incubation for the different sets of eggs. These data 
have been summarized into averages under the respective days of the 
hatching periods. (Tables XL VI and LX.) The curve of figure 15 
has been plotted from these combined data, and shows a marked 
shortening of time under a prevailing high temperature and a pro- 
longation of time under prevailing low temperature. 

Taking our readings directly from the curve of figure 15 we get the 
following average degrees of temperature for the different number of 
days of incubation: 



4days=83.6° F. or 28.7° C. 

5 days=77.0° F. or 25.0° C. 

6 days=72.8° F. or 22.8° C. 

7days=^70.0° F. or 2L.1°<\ 

8 days=67.5° F. or 19.7° C. 

9 days=65.5° F. or 18.6° C. 
10 days=64.0° F. or 17.8° C. 



11 days=62.7° F. or 17.0° C. 

12 days=61.8° F. or 16.6° 0. 

13 days=61.2° F. or 10.2° C. 

14 days=f)0.fi° F. or 16.0° 0. 

15 days=60.1° F. or 15.6° 0. 

16 days=59.8° F. or 15.4° C. 



THE CODLING MOTH IN MICHIGAN. 



45 



The eggs for these experiments were kept in the outdoor rearing 
shelter, subjected to the normal temperature. 

It should be remembered that -throughout these tests the tem- 
perature has been fluctuating and that the separate obsevations can 
be only approximately exact and we have therefore obtained a great 
latitude of variation in degrees of temperature for the respective days. 
The extent of this variation is shown in Tables XLYI and LX in the 
maximum and minimum records. Variation in the time of incuba- 
tion should not entirely be ascribed to inadequate methods of record- 




**f/rjf brood • o-Second brood of eo 05 



Fig. 15.— Curve showing relation of the temperature to the time of incubation of first-brood and second- 
brood eggs of the codling moth at Douglas, Mich., 1911. (From Tables XLIH and LVII.) (Original.) 

ing observations but also to natural influences other than tempera- 
ture. It has been constantly found that eggs deposited at the same 
time have varied several days in hatching. Moisture conditions no 
doubt also have a bearing upon the length of incubation. The 
writer has found that eggs do not hatch readily during the prevalence 
of extremeh r dry weather. 

The " critical" temperature for the eggs of the codling moth can 
not be determined from the present data. It is thcrevore not possible 
to establish the degrees of accumulated effective temperature required 
for hatching under any given degrees of temperature. 



46 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



FIRST-BROOD OP LARV.E. 



Time of hatching. — Tho earliest newly hatched larvae appeared in 
the field about June 7, eggs being deposited on May 28 and the first 
larva from the band records being collected June 27. The greatest 
number of larvae hatched between June 17 and July 7. A few isolated 
larvae hatched as late as July 20. 

Length of feeding period of transforming larvse. — The feeding period 
for the transforming larvae of the first brood was determined from 70 
individuals, as given in Table LV. The average length of feeding 
was 21.25 days, the maximum 29 days, and the minimum 15 days. 
These results show a shortening of the feeding period as compared 
with the records for 1910, which must have been due to the excep- 
tionally warm season of 1911. 



Table XLVII. 



-Length of feeding period of wintering larvse of the Jirsb brood, Douglas, 
Mich., 1911. 



No. 


Date of— 




No. 


Date of — 




No. 


Date 


of— 




of 




Days 

feed- 


of 




Days 
feed- 


of 






Days 
feed- 


ob- 






ob- 






ob- 








Hatch- 


Leaving 


ing. 




Hatch- 


Leaving 


ing. 




Hatch- 


Leaving 


ing. 


tion. 


ing. 


the fruit. 




tion. 


ing. 


the fruit. 




tion. 


ing. 


the fruit. 




1 


June 7 


July 11 


34 


10 


June 22 


July 12 


20 


19 


June 20 


July 24 


28 


2 


June 13 


July 6 


23 


11 


June 23 


July 13 


20 


20 


...do 


July 28 


32 


3 


June 15 


July 12 


27 


12 


June 24 


July 12 


18 


21 


...do 


...do 


32 


4 


...do 


July 14 


29 


13 


...do 


July 15 


21 


22 


...do 


Aug. 3 


38 


5 


June IS 


July 12 


24 


14 


June 20 


July 14 


18 


23 


June 27 


July 24 


27 


6 


...do 


July 23 


35 


15 


...do 


July 18 


22 


24 


...do 


July 30 


33 


7 


...do 


...do 


35 


16 


...do 


July 19 


23 


25 


...do 


...do 


33 


8 


June 19 


July 19 


30 


17 


...do 


July 20 


24 


20 


...do 


Aug. 7 


41 


9 June 20 


July 17 


27 


18 


...do 


July 23 


27 


.'7 


...do 


...do 


41 


















28.2 




















41 

18 







































Length of feeding period of wintering larvse. — On comparing records 
of the feeding period of the wintering larvae with those of the trans- 
forming larvae it will be noted that there is a marked difference, in that 
the wintering larvae fed for a much longer period of time. The aver- 
age for the wintering larvae is 28.2 days, the maximum 41 days, and 
the minimum 18 days (see Table XLVII) and for the transforming 
larvae the average is 21.25 days, the maximum 29 days, and the 
minimum 15 days (Table LV). This difference of habit of the two 
sets of larvae was also observed during 1910 and has been referred to 
in connection with the studies for that year. 

About one-half of the first-brood larvae recorded in Table LV were 
reared in bagged fruit on the trees, and the other half in fruit in cages. 



THE CODLING MOTH IN MICHIGAN. 47 

Within a week of the maturity of the larvae the bagged fruit was 
removed from the trees and placed in cages. The average length of 
feeding of larvae in bagged fruit was 20.96 days against 21 . 13 days for 
those reared in fruit in the cages, being a difference of less than 
half a day. 

Time of maturity of larvae. — From the band records the time of 
maturity and the relative abundance of full-grown larvae are deter- 
mined for field conditions. The Douglas band records (fig. 18) have 
been taken as typical and represent also the surrounding sections of 
the station. The first larva? were collected June 25 and subsequently 
in abundance throughout the season. It is estimated that the last 
larvae of the first brood appeared September 10. 1 

Percentage of transforming and wintering larvse. — Table LXVIII 
shows that 40 per cent of the iirst-brood larvae transformed and 60 
per cent wintered as larvae. The observations are from five sepa- 
rate band records. 

Larval life in the cocoon. — The larval life in the cocoon is here 
broadly considered to be the time necessary for the making of the 
cocoons, and is recorded from the time the larvae leave the fruit to 
the time of pupation. More closely considered, this period actually 
includes the time the larva searches for its hiding place and the pre- 
pupal stage, when the larva remains inactive and undergoes struc- 
tural changes previous to transformation. The wintering larvae of 
the first brood are not included here, as these remain in the larval 
stage until the following spring. The results of 132 observations 
(Table XL VIII) show a variation of 2 to 18 days and an average of 
7.2 days. The data for the extremely short periods of making of 
cocoons are somewhat misleading in that certain larvae in the act of 
making the cocoons have been disturbed by others and have then 
abandoned the first cocoon and made a new one. The records of 
Table XLVIII in such instances only show the time for the making 
of the last cocoon. The prolonged period of time as found in some 
cases is probably due to a diseased condition of these larvae. 

i For methods of determining the time of appearance of the last larvae of the first brood and the first 
larva' of the second brood see page 15. 



48 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XLVIII. — Length of the pupal stage of the summer brood, 


Douglas, 


Mich., 


1911. 


CD 


Date of— 


Days- 


& a 


Dale of— 


Days- 


.2 


Leaving 


Pupa- 


Emer- 
gence of 
moth. 


Making 

of 
cocoon . 


Pupal 


Leaving 


Pupa- 


Emer- 
gence of 
moth. 


Making 

of 
cocoon. 


Pupal 


o 


fruit. 


tion. 


period. 


d 


fruit. 


tion. 


period. 


1 


July 6 
...do.... 


July 9 
July 10 


July 22 
July 26 


3 


13 


69 




July 23 
...do 


Aug. 5 
Aug. 6 




13 


2 


4 


16 


70 


July 14 


9 


14 


3 


...do 


...do 


Julv 23 


4 


15 


71 




...do 


Aug. 7 




15 


4 


...do 


...do 


...do 


4 


13 


72 


Jaly 14 


Aug. 1 


Au.k. H 


18 


13 


5 


...do 


...do 


July 25 


4 


15 


73 


...do 


...do 


Aug. 15 


18 


14 


G 


...do 


...do 


July 23 


4 


13 


74 


Julv 15 


Julv 21 


Aug. 5 


6 


15 


7 


...do 


...do 


July 26 


4 


16 


75 


July 16 


Julv 24 


Aug. 7 


8 


14 


8 


do 


. do .... 


Julv 25 
July 24 


4 
4 


15 
14 


76 

77 




...do 


...do..... 




1) 


9 


f...do 


...do 


Julv 17 


Julv 21 


Auk. 5 


4 


15 


10 


...do 


...do 


...do 


4 


14 


78 


...do 


...do 


...do 


4 


15 


11 


...do 


...do 


Julv 23 


4 


13 


79 


...do 


July 23 


Aug. 6 


6 


14 


12 


...do 


...do 


...do 


4 


13 


80 


...do 


...do 


Auk. 7 


6 


15 


13 


...do 


...do 


...do 


4 


13 


81 


...do 


..do 


Aug. S 


6 


16 


14 


...do 


...do 


July 26 


4 


16 


82 


...do 


Julv 24 


Aug. 3 


7 


10 


15 


...do 


...do 


...do 


4 


16 


83 


...do 


July 25 


Aug. 7 


8 


13 


16 


...do 


...do 


July 28 


4 


18 


84 


...do 


July 26 


...do 


9 


12 


17 


...do 


...do 


July 27 


4 


17 


85 


...do 


Julv 27 


Aug. 8 


10 


12 


18 


...do 


July 11 


...do 


5 


16 


86 


.do 


Julv 2s 


Auk- '■» 


11 


12 


19 


...do 


...do 


...do 


5 


16 


87 


...do 


...do 


Aug. Hi 


11 


13 


20 


...do 


...do 


July 26 


5 


15 


,SN 


July 18 


Julv 24 


Aug. 7 


6 


14 


21 


...do 


...do 


Aug. 1 


5 


21 


89 


...do 


...do 


...do 


6 


14 


22 


...do 


...do 


July 27 


5 


16 


90 


...do 


Julv 25 


Aug. 6 


7 


12 


23 


...do 


...do 


July 26 


5 


15 


91 


...do 


...do 


Aug. 7 


7 


13 


24 


...do 


...do 


...do 


5 


15 


92 


...do 


...do 


...do 


7 


13 


25 


...do 


...do 


Julv 27 


5 


16 


93 


...do 


...do 


...do 


7 


13 


26 


...do 


...do 


...do 


5 


16 


94 


...do 


Julv 26 


...do 


8 


12 


27 


...do 


...do 


July 28 


5 


17 


95 


...do 


...d'o 


...do 


8 


12 


28 


...do 


...do 


Julv 26 


5 


15 


96 


...do 


...do 


...do 


8 


12 


29 


...do 


Julv 12 


July 28 


6 


16 


97 


...do 


...do 


...do 


8 


12 


30 


...do 


July 14 


July 27 


8 


13 


98 


...do 


...do 


...do 


8 


12 


31 


...do 


.. do 


July 30 


8 


16 


99 


...do 


...do 


...do 


8 


12 


32 


...do 


July 17 


Aug. 4 


11 


18 


100 


...do 


...do 


Aug. 8 


8 


13 


33 


July 9 


Julv 14 


Julv 30 


5 


16 


101 


...do 


...do 


...do 


8 


13 


34 


...do 


...do 


July 29 


5 


15 


102 


...do 


...do 


...do 


8 


13 


35 


...do 


...do 


Julv 31 


5 


17 


103 


...do 


Julv 27 


Aug. 7 


9 


11 


36 


...do 


...do 


Julv 29 


5 


15 


104 


...do 


...do 


Aug. 8 


9 


12 


37 


...do 


...do 


Julv 30 


5 


16 


105 


...do 


...do 


...do 


9 


12 


38 


...do 


...do 


July 29 


5 


15 


106 


...do 


...do 


...do 


9 


12 


39 


...do 


...do 


...do 


5 


15 


107 


...do 


...do 


...do 


9 


12 


40 


...do 


...do 


July 30 


5 


16 


108 


...do 


...do 


...do 


9 


12 


41 


...do 


Julv 15 


Julv 31 


6 


16 


109 


...do 


...do 


Auk. Hi 


9 


14 


42 


...do 


...do 


...do 


6 


16 


110 


...do 


...do 


Aug. 11 


9 


15 


43 


...do 


...do 


...do 


6 


16 


111 


...do 


Julv 28 


Aug. 7 


10 


10 


44 


...do 


July 17 


Aug. 2 


8 


16 


112 


...do 


...do 


Auk. 9 


10 


12 


45 


Julv 12 


...do 


July 31 


5 


14 


113 


...do 


...do 


...do 


111 


12 


46 


...do 


July IS 


Aug. 1 


6 


14 


114 


...do 


...do 


...do 


10 


12 


47 


...do 


...do 


Aug. 2 


6 


15 


115 


...do 


July 29 


Aug. 8 


11 


10 


48 


...do 


...do 


...do 


6 


15 


116 


...do 


...do 


Aug. 9 


11 


11 


49 


...do 


...do 


...do 


6 


15 


117 


...do 


...do 


Aug. 10 


11 


12 


50 


...do 


...do 


Aug. 3 


6 


16 


118 


...do 


...do 


...do 


11 


12 


51 


...do 


...do 


...do 


6 


16 


119 


Julv 19 


July 27 


Aug. 8 


8 


12 


52 


...do 


...do 


Aug. 4 
Aug. 2 


6 

7 


17 
14 


120 
121 


...do .... 




Aug. 5 

Auk. 9 


13 
9 




53 


...do 


Julv 1!) 


Julv 20 


Julv 29 


11 


54 




do ... . 


Aug. 3 
...do 




15 


122 


July 21 


July 30 
Aug. 2 


...do 


9 


10 


55 


July 12 


...do 


7 


15 


123 


...do 


Auk- 14 


12 


12 


56 


...do 


...do 


...do 


7 


15 


124 


...do 


Aug. 6 


Auk. 18 


16 


12 


57 


...do 


...do 


...do 


7 


15 


125 


Julv 23 


Julv 31 


Aug. 12 


8 


12 


58 


...do 


...do 


Aug. 4 


7 


16 


126 


...do 


...do 


...do 


8 


12 


59 




July 20 
...do 


Aug. 3 
Aug. 4 




14 


127 


.. do 


...do 


Aug. is 
Aug. 14 


8 


18 


60 


July 12 


8 


15 


128 


...do 


Aug. 8 


In 


6 


61 




...do 


...do 




15 


129 


July 24 


Aug. 1 
Aug. 2 


Aug. 15 
Auk. 16 


8 


16 


>2 




...do 


...do 




15 


130 


Julv 25 


s 


14 


63 


July 12 


...do 


Auk. 5 


8 


16 


131 


Julv 27 


Aug. 1 


Aug. 14 


5 


13 


64 




Julv 21 


Aug. 4 




14 


132 


Julv 29 


Aug. 6 


Am?. 22 


8 


16 


65 


July 12 


...do 


Aii» 5 


9 


15 














66 




...do 


...do 




15 


Average .. 




7.2 


14.0 


"7 


July 12 


Julv 2:5 


Aug. 5 


11 


13 


Maximum - - 


18 


21 


68 




...do 


...do 




13 


Mil 


limum 




3 


6 



















FIRST BROOD OP PUP/E OR SUMMER PUP/E. 



Time of jpwpation. — The time of pupation as represented in figure 
20 has been determined on the basis that the time and rate of emer- 
gence of the moths must be in close relation and in direct proportion 
to the time and rate of pupation. Observations on pupation in the 
rearing cages extended from July 6 to August 8. In the field, how- 



THE CODLING MOTH IN MICHIGAN. 



49 



ever, the pupation period was longer. From the records of emer- 
gence of moths we ibid that the earliest pupae must have appeared 
about June 30 and the last pupa 1 about August 24. 

Length of pupal stage.— In the course of rearing work two separate 
tests on the length of the pupal stage have been made. One of these 
(Tables XLVIII and XLIX) includes primarily observations on 
the pupal stage; the other (Table LV) contains observations on the 
life cycle of the insect. The results of Table XLVIII, including 132 
insects, show that the period varied from 6 to 21 days, with an aver- 
age of 14 days. The results from the life cycle series (Tables LV 
and LVI), covering 75 observations, showed a variation of 11 to 24 
days, and an average of 15.18 days. 

Table XLIX. — Length of pupal stage of the summer brood, Douglas, Mich., 1911; 
summary of Table XL VIII. 



Number 


Days 


Number 


Days of 


Number 


Davs 


Number 


Days of 


of obser- 


making 


of obser- 


pupal 


of obser- 


making 


of obser- 


pupal 


vations. 


cocoon. 


vations. 


period. 


vations. 


cocoon. 


vations. 


period. 


1 


3 


13 


9 


17 


14 


2 


10 


is 


4 


1 


6 


28 


15 


■> 


18 


21 


5 


4 


10 


5 


10 


24 


16 


17 


6 


3 


11 


8 


11 


1 


17 


10 


7 


25 


12 


1 


12 


3 


18 


23 


8 


21 


13 


1 


13 


1 


21 



Table L.- 



Time of emergence of moths of the summer brood from band records, Douglas, 
Mich., 1911. 





Band records. 


"3 
o 


Date of 
emer- 
gence. 


Band records. 




Date of 
emer- 
gence. 


p 



ft 


S 

o 
£ 

CO 

a 

s 


CD 

5 
| 

a 

CD 
Ph 


73 

a 

o 

i 

s 


O 

a 

w 
p 

a 

CO 

B 


<3 

"5b 
3 
O 

ft 


S 
o 

.S 
GO 

o 

M 

c3 


CD 
03 

a 


•6 

a 
o 

i 

3 

(3 

is 

CD 

y. 


O 

— 
C3 

w 

a 

o 

a 

- 


~C3 

o 


Julv 8 
July 9 
July 10 
July 11 
Julv 12 
July 13 
July 14 








2 


3 

4 
L'l 
16 


5 

4 
33 
32 

7 
38 
30 
15 
13 
15 
18 
18 
12 
13 
15 
18 
13 
16 
21 
15 
14 
19 
20 
35 
39 
16 
35 
29 
52 
40 
90 
CO 
60 
67 
39 
30 


Aug. 13 
Aug. 14 

All;;. 15 

Aug. In 
Aug. 17 
Aug. 18 
Aug. 19 
Aug. 20 
Aug. 21 
Aug. 22 
Aug. 23 
Aug. 24 
Aug. 25 
Aug. 26 
Aug. 27 
Aug. 28 
Aug. 29 
Aug. 30 
Aug. 31 
Sept. 1 
Sept. 2 
Sept. 3 
Sept. 4 
Sept. 5 
Sept. 6 
Sept. 7 
Sept. 8 
Sept. 9 
Sept. in 
Sept. ii 

Sept. 16 

Sept. 17 
Sept. 18 

Total . 


3 
6 

1 

1 


10 
13 
5 
6 
8 
12 
5 


6 
19 
10 

8 
6 
9 
3 
5 
2 
5 
2 
3 
2 
2 
1 
2 
2 


3 

i 
i 


3 
12 

1 

1 
3 


22 








53 


1 
1 

2 

1 

1 

2 
4 
1 


2 
2 
3 
j 
2 
2 
I 
1 
4 
2 
2 
1 
1 
6 
2 
2 
9 
6 
4 
4 
5 
4 
2 


4 
8 
4 

16 
9 
4 
2 

3 
3 
5 

1 
2 
1 
2 

2 

2 



2 
2 
2 
4 
13 


3 

5 


17 
L6 

18 


1 

1 

1 

1 
2 
1 
2 
3 
2 

2 

1 
4 
4 

2 

2 
2 
11 
7 
2 
5 
3 


17 
19 
9 

10 

11 

10 

n 

8 
10 
11 
8 
8 
10 
9 
7 
7 
11 
10 
19 
19 
4 

12 
13 
13 
1J 
17 
19 
13 
12 
6 
7 


22 






8 


Julv 15 
Julv 16 
July 17 
July 18 
July 19 
July 20 
July 21 
Julv 22 
July 23 
July 24 
Julv 25 
July 26 
July 27 
Julv 28 
Julv 29 
Julv 30 
Julv 31 






5 


3 

2 

2 
2 
1 

1 
2 

1 
2 


8 
5 
3 
1 
4 
3 
2 
2 
2 
1 

1 
1 
1 
2 
1 


4 
1 


4 
2 

1 
1 


21 
15 
6 

7 
l) 


1 
1 




8 
4 
5 






4 


1 
1 


3 


1 


3 
5 
3 


2 1 


4 
3 


9 

6 




1 
1 


3 


2 
I 


1 


5 
1 


Aug. 2 

Aug. 3 2 


5 7 
4 15 
4 12 
10 17 
4 12 
15 35 
14 16 




1 
1 

1 


1 
1 


1 


3 

2 


Aug. 4 
Aug. 5 
Aug. 6 
Aug. 7 
Aug. 8 
Aug. 9 
Aug. 10 
Aug. 11 
Aug. 12 


10 
8 
12 

4 
6 

5 

1 
3 








1 








1 












1 
1 
1 










19 
22 
9 
13 


20 
23 

.'ii 
7 














91 


287 




89 


440 1,279 



50 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



FIRST BROOD OF MOTHS OR SUMMER MOTHS. 

Time of emergence. — The records for emergence of summer moths 
are given in Table L, covering 1,279 observations from five separate 
band records. The codling-moth larvae from the band records at 
Benton Harbor, New Richmond, Douglas, Lake Shore, and Pent- 
water were all sent to the station at Douglas, and the observations 
on the date of issue of the moths were all made there. The curve of 
figure 16 represents the total emergence of moths and is based upon 
the records of Table L. It will be noted that there existed a striking 
similarity in the rate of emergence and that the time of emergence 




Fig. 1G. — Emergence curve of moths of the summer brood in 1911, at Douglas, Mich. (Original.) 

was practically the same for the different band records. Tliis may be 
due to the peculiar climatic conditions of 1911, when the spring 
opened up uniformly over the entire fruit belt — a rather unusual 
occurrence. It may also be that during the middle of the summer 
the seasonal conditions became equalized over the different sections, 
and produced a corresponding equalizing tendency upon the develop- 
ment of the codling moth. 

The emergence records for the summer moths are remarkable 
both in respect to time and r;ite of appearance of the moths. The 
earliest moths issued July 8, which emergence was 21 days earlier 
then that of the more normal season of 1910. During the early part 
of the emergence period, from July 10 to July 14, moths appeared 
in abundance. During the later half of July, however, they were less 



THE CODLING MOTH IN MICHIGAN. 



51 



numerous, while during the first half of August they were again 
very abundant, reaching a maximum August 7. During the remain- 
ing part of the emergence period, which extended to September 18, 
comparatively few moths appeared. 

Table LI. — Oviposition of moths of the summer brood in captivity, Douglas, Mich., 1911. 





Num- 


Hale of— 


Days— 














Num- 


ber 












From 


ber 


of 












time of 


of 


moths 


Emer- 


First 


Last 


Before 


Of 


emer- 


cage. 


per 


gence of 


ovipo- 


ovipo- 


ovipo- 


ovipo- 


gence to 




cage. 


mollis. 


sition. 


sition. 


sition. 


sition. 


last ovi- 
posi- 
















tion. 


1 


29 


July 10 


July 14 


July 20 


4 


7 


10 


2 


24 


July 11 


...do 


.T i 1 % '..4 


3 


11 


13 


3 


10 


July 12 


...do 


Aug. 1 


2 


19 


.'it 


4 


29 


Jul'v 13 


July 16 


Jtilv 27 


3 


12 


11 


5 


26 


July 14 


Jul'v 23 


July 24 


9 


2 


10 


6 


15 


July 15 


Jul'v 18 


Jul'v 26 


3 


9 


11 


7 


10 


July 16 


Jul'v 20 


Jul'v 28 


4 


9 


12 


8 


11 


Jul'v 20 


Jul'v 26 


Jul'v 31 


6 


6 


11 


9 


15 


Jul'v 21 


July 28 


Aug. 5 


7 


9 


15 


10 


16 


Jul'v 22 


...do 


July 30 


6 


3 


8 


11 


15 


Jul'v 23 


...do 


Aug. 4 


5 


8 


12 


12 


13 


July 25 


July 27 


...do 


2 


9 


10 


13 


25 


July 26 


Jul'v 31 


Aug. 1 


5 


2 


6 


14 


11 


July 27 


...do.. .. 


Aug. 2 


4 


3 


6 


15 


14 


Jul'v 28 


Aug. 1 


Aug. 7 


4 


7 


10 


16 


17 


Jul'v 29 


July 31 


Aug. 14 


2 


15 


16 


17 


18 


Jul'v 30 


Aug. 1 


Aug. 10 


2 


10 


11 


18 


30 


Jul'v 31 


Aug. 2 


Aug. 18 


2 


17 


18 


19 


37 


Aug. 1 


Aug. 6 


Aug. 7 


5 


2 


6 


20 


15 


Aug. 2 


Aug. 5 


Aug. 9 


3 


5 


7 


21 


38 


Aug. 3 


Aug. 6 


Aug. 15 


3 


10 


12 


22 


34 


Aug. t 


...do 


Aug. 16 


2 


11 


12 


23 


54 


Aug. 5 


Aug. 7 


Aug. 12 


2 


6 


7 


24 


35 


Aug. 6 


Aug. 8 


Aug. 13 


2 


6 


7 


25 


88 


Aug. 7 


Aug. 9 


Aug. 16 


2 


8 


9 


26 


55 


Aug. 9 


Aug. 11 


Aug. 17 


2 


7 


8 


27 


54 


Aug. lo 


Aug. 12 


Aug. 31 


2 


20 


21 


28 


27 


Aug. 12 


Aug. 13 


Aug. 23 


1 


11 


11 


29 


19 


Aug. 13 


Aug. 17 


Aug. 21 


4 


5 


8 


30 


47 


Aug. 14 


Aug. 16 


Aug. 25 


2 


10 


11 


31 


21 


Aug. 16 


Aug. IS 


Aug. 28 


2 


11 


12 


32 


16 


Aug. 17 


...do 


Sept. 3 


1 


17 


17 


33 


27 


Aug. is 


Aug. 21 


Aug. 2S 


3 


s 


10 


34 


23 


Aug. 21 


Aug. 22 


Sept. 14 


1 


24 


24 


35 

A vera 
Maxi; 
Minin 


15 


Aug. 22 


Aug. 25 


Sept. 3 


3 


10 


12 




3.2 


9.4 


11.6 




9 
1 


24 
2 


24 







Time of oviposition. — Observations on egg deposition by the sum- 
mer moths in captivity were made under conditions already described 
on page 14 for the spring brood. The results as presented in Table 
LI show that on an average the first eggs were laid 3 days alter the 
time of emergence of the moths and that oviposition extended on an 
average to 9.4 days. Within the various cages considerable variation 
will be noted; in one instance the first eggs were obtained the following 
day after the emergence, in another instance the ninth day: in one 
cage the last eggs were deposited the sixth day, and in another cage 
the twentv-fourth day after the time of emergence of the moths. 



52 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



On correlating the above .observations with the time of emergence 
of the moths it will be found that the oviposition period extended 
from about July 1 1 to September 25. However, very few eggs were 
laid during September, and not all of these hatched. The great 
majority of eggs were deposited during August. 

Table LII. — Length of life of male and female moths of the first brood; summary of 
records of 1,019 individual moths. 



Male. 


Female. 


Male. 


Female. 


Length 


Number 


Length 


Number 


Length 


Number 


Length 


Number 


of life. 


of moths. 


of life. 


of moths. 


of life. 


of moths. 


of life. 


of moths. 


Days. 




Days. 




Days. 




Days. 




1 


1 


1 


1 


18 


6 


18 


10 


2 


8 


2 


5 


19 


9 


19 


9 


3 


lii 


3 


6 


20 





20 


10 


4 


22 


4 


15 


21 


2 


21 


13 


5 


22 


5 


24 


22 


1 


22 


9 


6 


42 


6 


32 


23 


2 


23 


2 


7 


4G 


7 


27 


25 


1 


24 


2 


8 


48 


8 


G2 


26 


1 


26 


4 


9 


50 


9 


4G 


32 


1 


28 


1 


10 
11 
12 
13 
14 
15 
10 
17 


41 
30 
32 
18 
24 
12 
11 
12 


10 
11 
12 
13 
14 


53 
48 
43 
40 
33 
26 
22 
14 






29 
30 
32 
33 
37 


2 
1 
1 
1 

1 






















16 

17 


Total.. 


456 




563 





Table LIII. — Longevity of male and female moths of the first brood; summary of Table 

LII 



Observations. 


Life of 

male 

moths. 


Life of 
female 
moths. 




Days. 

9.57 
32 

1 


Days. 
11.49 
37 

1 




Minimum 



Length of life of male and female moths. — A summary of observations 
from 1,910 individual moths is recorded in Table LII. The condi- 
tion under which the moths were kept has already been referred to 
on page 39. As observed for the previous brood, the longevity of 
the males was shorter than that for the females. On an average the 
males lived 9.57 days and the females 11.49 days; the maximum 
length of life for the males was 32 days and for the females 37 days. 

It is of interest to note that the results obtained by the writer at 
North East, Pa., in 1909, 1 are almost identical with those given 
above; the average length of life for the males being 9.79 days and 
for the females 1 1 .47 days. 

i Bui. 80, Pt. VI, Bur. Ent., U. S. Dept. Agr., p. 91, 1910. 



THE CODLING MOTH IN MICHIGAN. 



53 



The females were found to be more numerous than the males, 
which was also observed in the spring brood of moths. 

Lengl/t <>f life cycle of the first generation. — In Table LIV are brought 
together the average results from observations for (he separate stages 
of the first generation. These data show that on an average there 
elapsed 53.59 days from the time of appearance of eggs of the first 
brood to the time of appearance of eggs of the second brood. Com- 
paring these results with those of the complete life-cycle series 
(Tables LY-LVI), there will be found a difference of results of less 
than one day. In the life-cycle tests 75 individual insects were 
under observation from the time of the deposition of the eggs to the 
time of emergence of the moths that resulted from these eggs. 

Table LIV. Summary of results from experiments on the separate stages of the first 
generation of the codling moth in 1911. 



Life cycle of first generation. 



Number of days. 



Average. Maximum. Minimum 



Incubation of eggs 

Feeding period of larvae . . . 

Making of cocoons 

Pupal stages 

Time before egg deposition 

Total 



7. 94 
21.25 

7.2 
14.0 
3.2 



53.59 



2'. I 



Table LV. — Life cycle of the first generation of the codling moth, as observed by rearing 

at Douglas, Midi., in 1911. 



No. 
of ob- 
serva- 
tion. 


Date of— 


Days for— 


Egg 
deposi- 
tion. 


Tinteh- Larva 
n m ': h leaving 

m fa- the fruit. 


Pupa- 
tion. 


Emer- 
gence of 
moth. 


Hatch- 
ing. 


Feed- 
ing. 


Making 

of 
cocoon. 


Pupal 
period. 


Total 

life 

cycle. 


1 
2 
3 
4 
5 
6 
17 
1 8 

Ml 

UO 
1 11 

1 12 

1 13 

1 14 

1 15 

1 Hi 

1 17 

1 18 

1 19 

120 

21 

22 

23 

21 

2.') 

26 


June 1 
..do 


Tune in 

...do 


July 4 
...do 


Julv 9 
Julv 11 

...do 

July 8 
July 20 
Julv 14 
Jury !t 

Julv 11 

...do 

...do 

July 18 
July lii 


July 22 


9 
9 
9 
8 
8 
8 
9 
9 
9 
9 
9 
9 
9 
9 
10 
10 
9 
9 
9 
9 
9 
9 
9 
9 
It 
9 


24 
24 
24 
23 
25 
2t i 
21 
L'ii 
23 
23 
23 
21 


5 

7 
4 

is 
5 
3 
3 
3 
3 

10 
7 


13 


51 


-..do 

Tune ■'• 

June ") 

....In 

Juno ti 

...do 

...do 

...do 

...do 

...do 

...do 


...do 

June 11 
June 13 

...do 

June 15 

...do 

...do 

...do 

...do 

...do 

...do 


...do 

...do 
Julv 8 
Julv 9 
Julv . (i 

July 8 

...do 

...do 

...do 

July 11 


July 27 


16 


50 


Aug. 8 
July 31 
Julv 23 
Julv 20 

...do 

...do 

Aug. 3 
Aug. l 

2 Julv 31 

-July 25 


13 
17 
14 
15 
15 
15 
lti 
10 


i.l 
."ni 
47 
50 
50 
50 
58 
56 
55 
49 


...do.... 


...do.... 












June 8 
...do 

June It 

...do 

...do 

...do 

June 11) 
do 


June is 

...do 

...do 

...do 

...do 

...do 

June 19 
do 


July 8 
Julv 12 
July 8 
July 9 

...do 

Julv 12 
July 8 
July 13 

Julv 14 

...do 

Julv 15 
Julv li 


July 11 
July 21 
July 12 
July 13 
Julv 18 

Julv 14 
Julv 13 
July 23 
...do.... 


20 
24 
20 
21 
21 
24 
111 
24 
25 

2.". 
26 
16 


3 
12 
4 
4 
9 
2 
5 
10 
9 
7 
7 
4 




Aug. 7 
July 31 
Julv 30 
Aug. 3 
July 31 
July 29 


14 

m 

17 

111 

17 
l(i 


(10 
52 
51 
55 
52 
49 


...do.. . 


...do ... 








...do 

do 


...do 

.. do . 


July 21 

Julv 22 
Julv in 


Aug. 5 


15 


50 


June 11 


.Illlle I'll 


July 23 


13 


42 



1 Bagged fruit; average feeding, 20.9 days. 



2 Pupated in fruit; average feeding, 21.4 days. 



54 



DECIDUOUS FRUIT TNSECTS AND INSECTICIDES. 



Table LV. — Life cycle of the first generation of the codling moth, as observed by rearing 
at Douglas, 'Mich., in 1911 — Continued. 



No. 
of ob- 
serva- 
tion. 



Date of— 



Days for — 



28 

29 

30 

31 

i 31' 

133 

1 34 

135 

36 

37 

38 

39 

40 

41 

42 

'43 

1 44 

145 

46 

47 

48 

lit 

150 

151 

152 

153 

154 

55 

5(1 

57 

158 

159 

1 (10 

61 

62 

(13 

(14 

65 

66 

67 

68 

69 

170 

1 71 

1 72 

73 

74 

75 



deposi- 
tion. 



June 11 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 

June 12 
...do.... 
...do...-. 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 

June 13 
...do.... 
...do.... 
...do..... 

Juno 14 

..do..... 
...do 

..do 

..do 

June 15 

..do 

..do 

June 16 

..do 

..do 

.Tunc 18 

..do 

..do 

..do 

..do 

June 19 
June 20 

..do 

..do 

..do 

..do 

..do 

June 26 
June 27 
...do 



Tlateh- 
ing. 



June 20 

...do 

...do 

...do 

...do 

...do. 

...do 

...do.... 
...do.... 
June 21 
...do.... 
...do.... 

...do 

...do.... 
...do.... 
...do.... 
...do.... 
..do.... 
...do.... 
June 22 
..do.... 
..do.... 
..do.... 
..do.... 
..do.... 
..do.... 
..do.... 
..do.... 
June 23 
..do.... 
..do.... 
..do.... 
..do.... 
..do.... 
June 24 
..do.... 
..do.... 
..do.... 
..do.... 
June 26 
June 27 

..do 

..do.... 

..do 

..do 

..do 

July 3 
Julv 4 
..do 



Larva 
leaving 
the fruit 



July 7 

..do 

Julv 9 
July 13 

..do 

July 7 
Julv 9 
..do.... 
Julv 13 
Julv 6 
July 8 
July 10 
..do.... 
..do.... 
July 11 

..do 

July 9 
July 15 



July 11 
..do.... 
Julv 12 
..do.... 
July 10 
Julv 11 

..do 

July 21 



July 9 
July 12 
July 18 
Julv 12 

..do 

Julv 13 
July 12 
July 17 
Julv 18 
Julv 20 
Julv 23 
Julv 15 
Julv 12 
Julv 24 



Julv 14 

..do 

July 20 
July 2S 

..do 

..do 



Pupa- 
tion. 



July 12 
...do.... 

July 13 
July 18 
Julv 20 
July 12 
Julv 13 
Julv 12 
July 19 
July 9 
July 14 
July 1(1 
July 15 
Julv 10 
..do.... 
Julv 15 
..do.... 



Emer- 
gence of 
moth. 



July 20 

July 18 

..do 

July 21 

Julv 15 

July 16 

July 17 

July 29 



July 14 

Julv 18 

Julv 26 

Julv 17 

July 19 

July 18 

July 27 

July 30 

..do 



July 28 

Julv 29 

Julv 26 

Julv 20 

July 29 

Ails.'. 4 

Julv 21 

Julv 23 

Julv 29 

Aug. 3 

..do 

Aug. 6 



Julv 29 
July 30 
Aug. 4 
Aug. 5 
July 28 
Julv 31 
July 28 
Aug. 4 
July 22 
July 31 
Aug. 1 
July 31 
Aug. 2 
Aug. 9 
July 31 

...do..... 
Aug. 8 

2 July 31 
Aug. 4 
..do..... 
Aug. 3 
Aug. 5 
July 31 
Aug. 1 

..do 

Aug. 10 
Aug. 1 
July 30 



Aug. 


8 


-Vug. 


2 


Aug. 


4 


Aug. 


1 



Aug. 10 



Aug. 9 

Aug. 10 

Aug. 9 

Aug. 5 

Aug. 10 

Aug. 18 

Aug. 5 

Aug. 6 

Aug. 1(1 

-Vim. 15 

..do 

Aug. 19 



Hatch- 
ing. 



Feed- 
ing. 



Making 

of 
cocoon. 



Pupal 
period. 



Total 

life 
cvcle. 



13 


54 


1(1 


47 


1(1 


49 


14 


4(1 


11 


53 



Bagged fruit; average feeding, 20.9 daj - 



2 Pupated in fruit; average feeding, 21.4 days. 



Table LVI. — Length of the life cycle of the first generation: summary of Table LV. 



Observations. 


Days for— 


Hatch- 
ing. 


Feeding. 


Making of 
cocoon. 


Pupal 
period. 


Total life 
cycle. 


A veragc 


8. 33 

10 



21.25 
29 

15 


6.54 
18 

2 


15.18 

24 
11 


51.10 
64 

42 









THE CODLING MOTH IN MICHIGAN. 55 

It is of interest to note the extent of variation in the length of the 
life cycle of the first generation. The figures of Table LIV show a 
maximum length of time for the entire life cycle of 87 days ami a 
minimum of 20 days, or a range of variation of 58 days. Prom the 
above results it becomes evident that reliable conclusions can not be 
made from a limited number of observations no matter how accurate 
the records may be; they only represent the results under limited 
conditions. Such conclusions may readily become extremely mis- 
leading when used as a basis for timing spray applications. By using 
the average length of the life cycle of 51 days it will be found that 
three broods of the codling moth could have existed in the Michigan 
fruit belt in 1911. Or should we, on the other hand, choose to use 
the records for the minimum length of the life cycle we could on that 
basis account for the existence of a fourth brood of the codling moth. 
Our observations, however, only show evidence of two broods, since 
out of several thousand larvae of the second brood not a single insect 
pupated in 1911. 

THE SECOND GENERATION. 
SECOXI> BROOD <il-' EGGS. 

Time of Incubation. — Eggs of the second brood occurred in the 
field for about three months. During this long period the different 
eggs were often subjected to strikingly different climatic conditions, 
which resulted in an unusual degree of variation in the time of incu- 
bation. In Table LVII are included the records for 110 observa- 
tions. The time of incubation here varied from (i to 10 days and 
averaged 9.35 days for the whole period. During the latter part of 
July and first half of August, when the greatest abundance of eggs 
was found, the time of incubation varied from to 8 da vs. As for 
the first brood of eggs, observations were also made on the embryo- 
logical development of the second brood of eggs, namely, the time of 
appearance of the "red ring" and the "black spot." The summa- 
rized results in Table LIX show 7 that the red ring appeared on an 
average within 3 days after c^ deposition and the black spot 2 days 
previous to hatching. A number of eggs deposited during the middle 
part of September failed to hatch, mostly due to the prevailing low 
temperature. The fact that the red ring had already appeared in 
these eggs proved them to be fertile. 

All of the eggs used in these tests were laid in the rearing cages, 
and there were 4,643 eggs under observation as listed in Table LVII. 



56 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table LVII. — Length of incubation of the second brood of eggs, and average tempera- 
ture during inedbation, Douglas, Mich., 1911. 







Date of — 


Duration of— 


"1 

Average 

mean 
temperar 


No. of 


Num- 
















i obser- 
vation. 


ber of 
eggs. 


Egg dep- 


Appear- 
ance of 
red ring. 


Appear- 
ance of 


Hatch- 


Red 


Black 


Incu- 






osition. 


black 
spot. 


ing. 


ring. 


spot. 


bation. 
















Days. 


Days. 


Days. 


°F. 


1 


18 


July 14 


July IS 


July 20 


July 22 


4 


6 


8 


66. 96 


2 


23 


July 15 


July 19 


July 21 


Julv 23 


4 


6 


8 


66.83 


3 


35 


July 17 


July 21 


July 23 


July 24 


4 


6 


i 


66. 00 


■1 


59 


July 18 


July 23 


July 25 


July 28 


5 


7 


10 


64.60 


5 


67 


July 19 


Julv 24 


July 27 


...do.... 


5 


S 


9 


64.18 


6 


15 


...do 


...do 


...do 


July 29 


5 


s 


10 


64. 07 


7 


64 


Julv 20 


July 26 


Julv 28 


...do 


6 


s 


9 


64. 35 


8 


8 


...do 


...do 


...do 


Julv 30 


6 


s 


10 


64. 73 


9 


5 


Julv 22 


Julv 27 


Julv 29 


Julv 31 


5 


7 


9 


65. 41 


10 


8 


...do 


...do 


...do 


Aug. 1 


5 


7 


10 


00.47 


11 


27 


July 23 


July 28 


Julv 30 


July 31 


5 


7 


8 


65. 09 


12 


25 


...do 


...do.... 


Julv 31 


Aug. 1 


5 


8 


9 


0b. MO 


13 


15 


July 24 


July 29 


...do 


...do 


5 


7 


s 


66.63 


14 


17 


July 26 


July 31 


Aug. 1 


Aug. 2 


5 


6 


7 


69. 20 


15 


12 


July 27 


...do 


...do.... 


...do.... 


4 


5 


6 


70.33 


16 


4 


...do.... 


...do 


...do.... 


Aug. 3 


4 


5 


7 


69. 76 


17 


12 


July 28 


Julv 30 


Aug. 2 


...do 


2 


5 


6 


70.70 


18 


4 


...do 


...do 


...do 


Aug. 4 


2 


5 


7 


70. OS 


19 


14 


Julv 29 


Aug. 2 


Aug. 3 


...do 


4 


5 


6 


70.23 


20 


3 


...do.... 


...do.... 


...do 


Aug. 5 


4 


5 


7 


70.22 


21 


172 


Julv 30 


...do.... 


Aug. 4 


...do 


3 


5 


6 


70.55 


22 


12 


...do.... 


...do 


...do 


Aug. 6 


3 


5 


7 


71.00 


23 


95 


Julv 31 


...do.... 


Aug. 5 


...do 


2 


5 





70. ."4 


24 


30 




...do.... 


...do 


Aug. 7 


2 


5 


7 


71.07 


25 


46 


Aug. 1 


Aug. 3 


...do 


...do 


2 


4 


6 


70. 25 


26 


22 


...do 


...do 


Aug. 6 


Aug. 8 


2 


5 


7 


71.22 


27 


72 


Aug. 2 


Aug. 4 


Aug. 7 


...do 


2 


5 


('. 


71.29 


28 


4 


...do...: 


...do 


...do 


Aug. 9 


2 


5 


7 


71.01 


29 


40 


Aug. 3 


Aug. 5" 


Aug. 8 


...do 


2 


5 


6 


71.81 


30 


8 


...do.... 


Aug. 6 


...do 


Aug. 10 


3 


5 


7 


71.74 


31 


30 


Aug. 4 


...do 


Aug. 9 


Aug. 11 


2 


5 


7 


72.61 


32 


111 


Aug. 5 


Aug. 8 


Aug. 10 


...do 


3 


5 





73.01 


33 


17 


...do 


Aug. 7 


...do.... 


Aug. 12 


2 


5 


7 


72.20 


34 


146 


Aug. 6 


Aug. 8 


Aug. 11 


...do 


2 


5 


6 


71.95 


35 


60 


...do 


...do 


...do 


Aug. 13 


2 


5 


7 


71.00 


36 


188 


Aug. 7 


...do 


Aug. 12 


Aug. 14 


T 


5 


7 


69.97 


37 


18 


...do 


...do 


Aug. 13 


Aug. 15 


i 


6 


S 


70.39 


38 


309 


Aug. S 


Aug. 11 


Aug. 34 


...do.... 


3 


6 


7 


66.59 


39 


3 


...do 


...do 


...do 


Aug. 16 


3 


6 


s 


69.47 


40 


3 


Aug. 9 


Aug. 12 


...do 


Aug. 15 


3 


5 


6 


69. 47 


41 


99 


...do 


...do 


...do 


Aug. 16 


3 


5 


7 


09. 49 


42 


13 


...do 


...do 


Aug. 15 


Aug. 17 


3 


i\ 


s 


69.96 


43 


298 


Aug. 10 


Aug. 13 


...do.... 


...do 


3 


5 


7 


09. NO 


41 


4 


...do 


...do 


...do 


Aug. IS 


3 


5 


8 


69.99 


45 


310 


Aug. 11 


...do 


Aug. 16 


Aug. 17 


2 


5 


6 


69.33 


46 


130 


...do 


Aug. 14 


...do 


Aug. 18 


3 


5 


7 


a\. 56 


17 


37 


...do 


...do 


Aug. 17 


Aug. 19 


3 


6 


8 


69. 15 


4S 


128 


Aug. 12 


Aug. 15 


...do 


Aug. 18 


3 


5 


o 


69.92 


49 


37 


...do 


...do 


...do 


Aug. 19 


3 


5 


7 


09.40 


50 


130 


Aug. 13 


Aug. 16 


Aug. 18 


Aug. 20 


3 


6 


7 


os. f,5 


51 


102 


...do.... 


...do 


...do 


Aug. 21 


3 


6 


8 


67.68 


52 


87 


Aug. 14 


Aug. 17 


Aug. 19 


...do 


3 


5 


7 


07. 77 


53 


58 


...do... . 


...do 


Aug. 20 


Aug. 22 


3 





8 


07. SO 


54 


198 


Aug. 15 


...<!o 


Aug. 21 


...do.... 


2 


6 


7 


07. 07 


55 


08 


...do.... 


...do 


...do 


Aug. 23 


2 


6 


8 


66.85 


56 


8 


...do.... 


...do 


...do 


Aug. 24 


2 


6 


9 


66.08 


57 


8 


...do 


...do 


Aug. 22 


Aug. 25 


2 


7 


10 


or.. 40 


58 


37 


Aug. 16 


Aug. 19 


Aug. 23 


Aug. 24 


3 


7 


s 


65.63 


59 


17 


...do.... 


...do 


...do.... 


Aug. 25 


3 


7 


9 


66.04 


60 


27 


...do 


Aug. 20 


Aug. 24 


Aug. 26 


4 


8 


10 


64.23 


61 


8 


...do 


...do 


...do... . 


Aug. 27 


4 


8 


11 


01. 10 


62 


21 


Aug. 17 


Aug. 19 


...do... . 


Aug. 20 


2 


' 


9 


63.22 


63 


39 


...do.... 


Aug. 20 


Aug. 25 


Aug. 27 


3 


8 


10 


63.24 


64 


40 


...do 


...do.... 


...do 


Aug. 28 


3 


8 


11 


63.72 


65 


206 


Aug. 18 


...do 


Aug. 26 


...do.... 


2 


8 


10 


62.99 


66 


18 


...do.... 


...do.... 


Aug. 27 


Aug. 29 


2 


9 


11 


62.97 


67 


26 


Aug. 19 


Aug. 21 


Aug. 28 


Aim. 30 


2 


9 


11 


02.00 


68 


4 


...do.... 


...do.... 


...do... . 


Aug. 31 


2 


9 


12 


61.69 


69 


119 


Aug. 21 


Aug. 23 


Aug. 30 


Sept. 1 


2 


9 


11 


01.71 


70 


28 


...do 


...do 


...do.... 


Sept. 2 


2 


'J 


12 


62.36 


71 


32 


Aug. 22 


Aug. 25 


...do 


Sept. 1 


3 


8 


10 


61.03 



THE CODLING MOTH IN MICHIGAN. 



57 



Table LVII. — Length of incubation of the second brood of eggs, and average tempera- 
ture during incubation, Douglas, Mich., 1911 — Continued. 



No. of 
obser- 
vation. 



81 
82 
83 
84 
85 
86 
87 
88 
SO 
90 
91 
92 
93 
94 
95 
96 
97 
98 
99 
100 
101 
102 
103 
104 
105 
106 
107 
108 
109 

no 



Num- 
ber of 
eggs. 



Date of- 



Egg dep- 
osition. 



A ppear- 
ance of 
red ring. 



Aug. 22 
Aug. 24 
..do.... 

Aug. 20 
Auk. 27 
..do. . . . 



Aug. 28 
..do... 

..do... 
..do... 
Aug. 30 
..do... 
Aug. 31 
..do... 
Sept. 2 
Sept. 8 
..do.... 
Sept. 9 
..do... 
..do... 

Sept. 10 

..do... 

..do... 
Sept. 11 
..do... 
..do... 
..do... 
Sept. 12 
..do... 



Sept. 13 

..do... 
..do... 
..do... 
..do... 
Sept. 14 

Sept. 17 
..do... 
..do... 



Aug. 
Aug. 
...do. 
Aug. 
A.ug. 
do. 



...do. 
...do. 

Sept. 
...do. 
Sept. 
..do. 

Sept. 

...do. 

Sepl. 
Sept. 
..do. 

s x. 

..do. 
Sept. 
..do. 
...do. 
Sept. 
..do. 
Sept. 
..do. 
..do. 
..do. 



Sepl. 

..do. 

..do. 
..do. 
..do. 
..do. 
..do. 

Sept. 

..do. 
..do. 



Appear- 
ance of 
black 
spot. 



Hatch- 
ing. 



Aug. 

.». 

...do. 
Sept. 
...do. 

. S X: 
.«. 

Sept. 

...do. 

.fS 

Sept. 

Sept. 

...do. 
Sept. 

Sept. 
...do. 

Sept. 
...do. 

Sept. 
...do. 
...do. 

Sept. 
Sepl. 

...do. 

...do. 
...do. 
...do. 
Sept. 
...do. 
...do. 

Sept. 

Sept. 
Sept. 

...do. 
...do. 



Sept, 2 
Sept. 4 
Sept. 5 
...do... 
..do... 

Sept. li 

..do... 
Sept. 7 
Sept. s 

S X:.:' 

Sept. 10 
..do... 

Sept. 11 
Sept. 15 
Sept. IS 
Sept. 19 
..do... 
Sept. 20 
Sepi . 25 
Sept. 21 
Sept. 22 
Sept. 24 
Sept. 22 
Sept. 23 
Sept. 24 
Sept. 25 
Sept. 24 
Sept. 25 
Sept, 24 
Sept. 25 
Sept. 20 
Sepl. 27 
Sept, 28 
Sept, 24 
Sept. 28 
Sept. 29 
Oct. l 
Oct. 3 



Duration of— 



Red 
ring. 



Days. 
3 
2 
2 

4 
4 
4 
3 
3 
4 
4 
3 
3 
3 
3 
4 
3 
3 
3 
3 
3 
3 
3 
3 
4 
4 
5 
5 
4 
4 
4 
4 
4 
4 
4 
3 
3 



Black 

spot. 



Days. 
8 
9 
9 



Incu- 
bation. 



Days. 
11 
11 
12 
in 


10 

9 
10 
11 
12 

to 
11 

10 

n 

13 
10 
11 
10 
11 
16 
11 
12 
14 
11 
12 
13 
14 
12 
13 
11 
12 
13 
14 
15 
10 
14 
12 
14 
16 



Average 
me in 

tempera- 
ture. 



"F. 

61.81 

61.96 

62.23 

62.95 

62.90 

03.17 

62. 59 

62.41 

62.39 

62. 84 
63.58 
63. 27 

63. 77 
63.60 
62. 14 
62. 40 
62.85 

02.34 

62.06 

61.09 

m. SO 

01.30 
61.09 
61.35 
60.92 
01 . 03 
61.11 

00.71 
00. SI 

61. io 
61. 27 
00. 93 
60. 43 
60.47 
61.68 
00.70 
59.00 

58. 55 

57. SO 



Table LVIII. — Length of incubation of second-brood eggs laid in rearing cages, Douglas, 
Mich. ,'1911; summary of Table L VLT. 



Appearance of red 
ring. 


A ppearance of black 
spot. 


Total incubation 
period. 


Number 
of days. 


Number 
of obser- 
vations. 


Number 
of days. 


Number 
of obser- 
vations. 


Number 
of days. 


Number 
of obser- 
vations. 


1 
2 
3 
4 
5 
6 
8 


2 
27 
41 
24 
11 
2 
3 


4 

5 
6 
7 
8 
9 
10 
11 


1 

30 
15 
12 
is 
22 
11 
1 


6 

7 
8 
9 
10 

11 
12 
13 
14 
15 
13 


13 
22 
13 

9 
17 
15 

9 

4 
5 

1 
2 































58 



DECIDUOUS FEUIT INSECTS AND INSECTICIDES. 



Table LIX. — Length of incubation of second-brood eggs laid in rearing cages, Douglas, 
Mich., 1911; summary of Tables L VII and L VIII. 



Observations. 


Number of days — 


For appear- 
ance of red 
ring. 


For appear- 
ance of 
black spot. 


For incu- 
bation. 




3.33 

8 

1 


7.19 
11 
4 


9.35 
16 
* G 









Effect of temperature upon the time of incubation. — The general effect 
of the temperature upon the time of incubation of the codling moth 
eggs has already been considered on page 44 and the results for the 
second brood of eggs have there been given in the diagram (fig. 15) 
together with those for the first brood. In Table LVII the average 
daily temperature is given for the 110 separate observations. These 
temperature records have further been summarized to averages for 
the respective days of incubation as given in Table LX. The range 
in variation of average degrees of temperature for the different days 
is shown in the same table in the columns of maximum and minimum. 

Table LX. — Average mean temperature during incubation of second-brood eggs, Douglas, 
Mich., 1911; summary of Table L VII 



Days of 


Number 


Average mean temperature. 


incuba- 


i f obser- 












tion. 


vations. 


Average. 


Maximum. 


Minimum. 






° F. 


° F. 


° F. 


6 


13 


70.72 


73.01 


69.33 


7 


22 


69. 79 


72. 61 


66.00 


8 


13 


07.88 


70. 39 


65. 09 


9 


9 


04. 50 


66.30 


62. 59 


10 


17 


63. 51 


00.47 


01.03 


11 


15 


02. 40 


04.10 


61.19 


12 


9 


01.45 


62.84 


59.60 


13 


4 


01.23 


02.14 


60.81 


14 


5 


00. 39 


01.11 


58.55 


15 
16 


1 
2 


60.47 
59. <4 






61.09 


57.80 



SECOND BROOD OF LARV.E. 



Time of hatching. — In the field the hatching period extended from 
July 18 to October 3. The great majority of larvae hatched during the 
latter part of July and throughout August; during September only a 
few appeared. The period of hatching of larva? of the second brood, 
extending over two months and a half, is very exceptional in compari- 
son with the records for a normal season. During 1910 the period of 
hatching of eggs of the second brood was less than one month and a 
half. 



THE CODLING MOTH IN MICHIGAN. 59 

Table LXI. — Length o/feeding period of second-brood larvae, Douglas, Mich., 1911. 





Date of— 






Date of— 






Date of— 




No. of 






Davs 
of 


No. of 
obser- 






Days 


No. of 
obser- 






Days 
of 


obser- 














va- 
tion. 


Hatch- 
ing. 


Leaving 
fruit. 


feed- 
ing. 


va- 
tion. 


Hatch- 
ing. 


Lenving 
fruit. 


feed- 


va- 
tion. 


Hatch- 
ing. 


Leaving 
fruit. 


feed- 
ing. 


1 


July 23 


Aug. 18 


26 


(9 


All'.'. 12 


Oct. i" 


59 


137 


Aug. 20 


Oct. 7 


48 


2 


...do 


Aug. 19 


27 


70 


...do 


Oct. 12 


61 


138 


.do 


...do 


48 


3 


Julv 21 


...do 


26 


71 


...do 


Oct. 20 


C9 


139 


...do 


...do 


48 


•1 


...do 


Aug. 21 


28 


72 


Aug. 1") 


Sept. i 


20 


140 


...In 


Oct. 8 


49 


5 


...do 


Aug. 28 


35 


73 


...do 




22 


111 


...do 


Oct. 11 


52 





...do 


...do 


35 


74 


...do 


Sept. 17 


33 


142 


...do 


Oct 13 


54 


7 


...do 




43 


75 


...do 


33 


143 


Aug. 21 


Sept. 21 


31 


8 


Julv 2s 


Aug. 19 


22 


76 


...do 


Sept'w" 


34 


144 


.do 


Sept. 26 


36 


9 


...do 




22 


77 


...do 


Sept. 19 


35 


145 


...do 


...do 


36 


10 


...do 


Aug. 20 


23 


78 


..do 


Sept. 26 


42 


L46 


...do 


Oct l 


41 


11 


...do 




24 


7'.) 


- .do 




44 


147 


..do 


Oct. 3 


43 


12 


...do 


...do 


21 


80 




.do.. .. 


44 


148 


...do 


Oct. 6 


46 


13 


...do 


...do 


24 


Bl 


.do 


Sept. 29 


■ 


14!) 


...do 


Nov. 13 


84 


14 


...do 




25 


82 




Sep!. 12 


27 


150 


Auk. 22 


Sept. 29 


38 


15 


...do 


Aug. 26 


29 


83 


...do 


Sept. M 


29 


151 




..do 


38 


10 


...do 


Aug. 27 


30 


84 




J'.i 


152 


...do 


...do 


38 


17 


...do 


Aug. 2s 


31 


3£ 


...do 


's'ept'iT 


32 


153 


.do 


Oct 7 


46 


18 


...do 


...do 


31 




...do 


...do 


32 


154 


.do 


Oct. 8 


47 


19 


...do 


Aug. 29 


32 


87 




...do 


32 


155 


...do 


Oct. 14 


53 


20 


...do 


- 


35 


88 






39 


156 


...do 


Oct. 16 


55 


21 


...do 


Sept. 2 


36 


89 


..do 




41 


157 


Aug. 23 


Oct 1 


39 


22 


...do 


...do 


30 


90 


...do 


i 


71 


158 


...do 


Oct. 3 


41 


23 


...do 


Sept. 4 


38 


91 


Aug. 17 


i 


22 


159 


...do 


Oct. 6 


44 


24 


Julv 29 


Auk. 21 


23 


92 


...do 




29 


160 


...do 


...do 


44 


25 


...do 


...do 


23 


93 


...do 


Sei !. 17 


31 


161 


...do 


Oct. 16 


54 


26 


...do 


...do 


23 


94 


...do 




31 


162 


Aug. 24 


Sept. 29 




27 


...do 


...do 


2 J 


95 






33 


163 


..do 


...do 


36 


28 


..do 


Aug. 21 


26 


96 


...do 


Sept. 22 




164 


...do 


Oct. 3 


40 


29 


...do 


...do 


20 


97 


...do 






165 


...do 


...do 


40 


30 


...do 


Aug. 29 


31 


98 


..do 


...'In 




166 


Aug. 25 


Sept. 28 
...do 


34 


31 


Julv 31 


Aug. 28 


28 


99 


...do 


.do 


36 


167 


...do 


34 


32 


...do 


...do 


28 


100 


...do 


Set i. 23 


37 


168 


...do 


Oct 7 


43 


33 


...do 


Aug. 31 


31 


101 


...do 


...do 


37 


169 


.do 


Oct 20 


56 


34 


...do 


Sept. 7 


38 


1D2 


...do 


...do 


37 


17(1 


Auk. 26 


Sept. 2s 


33 


35 


Aug. 4 


Aug. 2S 


24 


103 


...do 


Sept. 24 


38 


171 


...do 


Oct. 6 


41 




...do 


Aug. 29 


25 


104 


..do 


38 


172 


...do 


Oct. 15 


50 


37 


...do 


Sept. 7 


34 


105 


...do 


Sept 26 


40 


173 


...do 


Oct. 16 


51 


38 


...do 


Sept. 9 


36 


106 


...do 


40 


174 


...do 


...do 


51 


39 


Auk. 6 


Sept. i 


29 


1D7 


...do 


"!do""; 




17.-, 


...do 


Oct. 17 


52 


40 


...do 


...do 


21) 


108 


..do 


.do.... 


40 


176 


...do 


Oct. 20 


55 


41 


...do 


...do 


29 


11)9 


...do 


..do 


40 


177 


...do 


Oct. 23 


58 


42 


...do 


Sept. n 


36 


110 


...do 


Sept. 29 


43 


178 


Aug. 27 


Oct. 8 


42 


43 


...do 


Sept. 16 


41 


111 


...do 


.do 


43 


179 


..do 


Oct. 9 


43 


44 


...do 


Sept. 26 


51 


112 


...do 


...do 


43 


180 


...do 


Oct. 15 


49 




Aug. 7 


Aug. 28 


21 


113 


..do 


Oct. i 


■ 


181 


...do 


Oct 16 


50 


4(i 


...do 


Sept. 4 


28 


114 


...do 


..do 


45 


182 


Aug. 28 


Oct. 14 


47 


47 


Aug. 11 


...do 


24 


115 


...do 


...do 


45 


183 




Oct. 17 


50 


48 


...do 


Sept. 11 


31 


116 


...do 


...do 


45 


184 


..do 


Oct. 20 


53 


■ill 


...do 


31 


117 


..do 


...do 


45 


185 


...do 


...do 


53 


50 


...do 


Sept'.'ii'' 


32 


118 


...do 


Oct. ii 


50 


186 


Sept l 


Oct. it 


43 


51 


...do 


Sept. 14 


34 


119 


...do 


Oct. 14 


58 


is; 


. 


Oct. 26 


54 


52 


...do 


Sept. 16 




120 


...do 


Oct. is 


62 


188 


. ..do 


Oct. 19 


45 


53 


...do 


Sept. 17 


37 


121 


..do 


Oct. 20 


64 




Oct. 20 


46 


54 


...do 


37 


122 


...do 


>"ov. 1 


76 


190 


...do 


Oct. 23 


49 


55 


...do 


Sept.' 19 " 


39 


123 


Au ',. 18 


- 


32 


191 


...do 


Nov. 13 


70 


56 


...do 


Sept. 26 


46 


124 


..'.do 




41 


192 


...do 


...do 


70 


."■7 


..do 


Oct. in 


60 


1 25 


...do 


Sept. 29 


42 


193 


..do 


...do 


70 


58 


...do 


Oct. 11 


il 


126 


..do 


Oct. 3 


46 


194 


Sept. •") 


...do 


69 




Auk. 12 


Sept. 7 


26 


127 


..do 


Nov. in 


84 


195 


Sept. s 


Oct 19 


41 


<0 


..do 


Sept. 11 


o 


128 


Auk. 20 


Sept. 13 


21 


196 


Sept. in 


Oct 20 


in 


61 


...do 


Sept. 12 


31 


■ 


.do 


Sept. 1!) 


:{() 


197 


..in 


Nov. 10 


61 


62 


...do 


Sept. 13 


32 


130 


...do 


Sept. 22 


33 


198 


.do 


Nov. 13 


64 


63 


...do 


Sept. 14 


33 


131 


...do 


33 


199 


Sept. 11 


Oct. 26 


45 


64 
65 


...do 

...do 


Sept. 18 


37 
37 


132 
133 


...do 

..do 


...do'.'.'.'.'. 
...do 


33 
33 


















...do 


Sept'w' 


• 


134 


...do 


Sept. 26 


37 




40.03 




...do 


.do 




135 


...do 


...do 


37 


Maximum 


B4 


68 


...do 


Oct. 7 


56 


i3t; 


...do 


Sept. 2s 


39 




20 



35215°— Bull. 115, pt 1—12 5 



GO 



DECIDUOUS FRUIT INSECTS AND [NSECTICIDES. 



Table I. XII. Length of feeding period of second-brood larvae, Douglas, Mich., 1911; 

summary of Table LXI. 



Number 


Days of 


Number 


Days of 


Number 


Days of 


Number 


Pays of 


of larvae. 


feeding. 


of larva?. 


feeding. 


of larvae. 


feeding. 


of larvae. 


feeding, i 


l 


20 


7 


32 


4 


44 


2 


56 


I 


21 


9 


33 


8 


45 


2 


58 


4 


22 


S 


34 


."> 


46 


1 


59 


5 


23 


4 


35 


2 


47 


1 


lill 


6 


24 


13 


36 j 


3 


48 


3 


.'.1 


2 


25 


9 


37 


3 


49 


1 


62 


5 


26 


9 


38 


4 


50 


2 


64 


2 


27 


4 


39 


3 


51 


2 


69 


4 


28 


8 


40 


2 


52 


3 


70 


7 


29 


7 


41 


3 


53 


1 


71 


3 


30 


3 


42 


3 


54 


1 


76 


10 


31 


8 


43 


2 


55 


2 


si 



Length of feeding period. — The feeding period of the second-brood 
larvae is considerably longer than has been recorded for the first-brood 
larvae and is mainly the result of prevailing low temperatures during 
the late summer and the fall. The data from 199 observations 
(Table LXI) cover a long period of time extending from July 23, when 
the earliest larvae hatched, to November 13, when the last larvae left 
the fruit. There was a range in the length of the feeding period of 
from 20 to 84 days, with an average of 40 days. 

Time of maturity. — In the rearing cages the first larvae of the second 
brood left the fruit August 18, but these were not from the earliest 
eggs. Considering the time of feeding and the date of earliest ovi- 
position, it is evident that in the field the first larvae left the fruit about 
August 13. As noted from the band records, the last larvae left the 
fruit November 13, which was also the last date of observation in the 
rearing cages. 

BAND RECORDS OF L911. 

During 1911 the band-record tests were extended to the following 
five localities: Benton Harbor, New Richmond, Douglas, lake shore 
(near Douglas), and Pent water. The purpose of these tests in the 
widely separated sections of the Michigan fruit belt was to determine 
the possible existence of differences in the time of development of the 
codling moth. 

The different band-record orchards were located respectively near 
Benton Harbor, 7 miles from the lake; at Douglas, on the grounds of 
the station 2 miles from the lake; at the lake shore, west of Douglas; 
and near Pent water, about 7 miles from the lake. Most of the apple 
trees were old and none of them had been sprayed with poison. The 
number of trees and varieties of apples, so far as could be determined, 
were as follows: At Douglas, two trees Golden Russet, one Rhode 
Island Greening, one crab apple; at the lake shore, one King, two 
Canada Red, one Wealthy, one Astrachan, two winter varieties not 
determined ; at New Richmond, two Baldwin, one Transcendent crab 
apple, one winter variety not determined; at Benton Harbor, one 
Golden Russet, one Canada \iri\, one crab apple, three fall varieties 
not determined ; at IVntwater, six Ben Davis. 



THE CODLING M'tTH IN MICHIGAN, 



61 







Table LXIII. Band records at Douglas, 


Mkh., 


/.'///. 






No. of 

record. 


Date of 

collect- 
tag. 


Num- 
ber of 
larva:. 


Wmar Emer- 

1.111. l9n 


Num- 
ber ol 
win- 
tering 
larva;. 


No. of 
record. 


Dale of 

collecl - 
tag. 


Num- 
ber of 

larva'. 


Ktner- 
1911. 


Emer- 
gence ol 
para- 

1911. 


Num- 
ber of 
win- 
tering 
larva?. 


i 

2 

3 

4 

•") 

6 

7 

S 

9 

10 

11 

12 

i:i 

14 

15 

16 

17 

18 

li) 

20 

21 

22 

23 

24 

25 


June 25 
June 28 

Julv 1 
Julv 1 
Julv 7 
Julv ID 
Julv 13 
Julv IC 
Julv 19 
Julv 22 
Julj 25 
Julv 28 
Julv 31 
Aug. 3 
Auk. 6 
Auk. 9 
Aug. 12 
Auk- 15 
A UK- 18 

Aug. -'i 

Aug. 24 
Aug. '-'7 
Aug. 30 
Sept. -' 
Sept. 5 


I 

2 
3 

2 
15 
9 






i 


l 




'.) 

2 
1 

1 

ii 
6 
I 
13 
3 
10 
Hi 
24 
21 
12 
10 
14 
8 
3 
9 
13 


26 

27 

2s 

29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 


Sept. ii 
Sept. ii 
Sept. 17 
Sept. 2n 
Sept. 23 
Sept. 26 

Oct. 2 
Oct. :> 

Del. 8 

Oct. n 
Oct. M 

Oct. 17 
Oct. 211 

Oct. 23 
Oct. 20 
Oct. 29 

Nov. 1 
Nov. 4 
Nov. 7 
Nov. 10 
Nov. 13 


• 
13 
11 
20 
17 
19 
20 
27 

s 

111 

6 
16 

10 
17 

2 
1 
II 



2 
1 






9 

13 
II 
20 

17 
1!) 
20 

27 

s 

111 

1. 

10 

III 

17 

3 

2 
1 




2 
1 


2 
2 
















2 

:. 

7 


1 

6 

1 

2 
4 
3 

1 

1 














21 11 

is U 










21 
11 

13 

17 
7 
16 

2li 
2s 
21 
12 
li) 
14 

3 
9 
13 


20 

3 

:. 
1 

3 
ii 
3 
4 






















































































Total 


517 


91 


19 


407 













At Benton Harbor, New Richmond, and Pentwater the larvae were 
collected respectively by Miss Clara Jakway, Mr. G. W. Tibbits, and 

Mr. S. J. Taylor, who sent the collected larva 1 for each observation to 
the station at Douglas. Mailing cases (see tig. 17) containing small 
blocks of corrugated pasteboard were used and proved very satis- 
factory. Very few larva' were injured during transportation, and 
not a single shipment was lost during the whole season. At the 
Douglas and lake shore orchards the larvae were collected by the 
stall" of the station. 

Table LXIV. Band records of 1911 at Benton Harbor, Mick.; larva collected by M> 

( 'Inra Jakway. 



No. of 

record. 


hale of 


Num- 


collect- 
tag. 


ber of ' 
Ian bb. 


l 


June 25 


12 


2 


June 28 


58 


3 


Julv 1 


71 


4 


Julv 1 


120 


.", 


Julv 7 


103 


6 


Julv in 


<)4 


7 


Julv 13 


01 


s 


Julv 10 




'J 


Julv 19 


30 


10 


Julv 22 


i 


11 


Julv 2.'. 




12 


Julv 2s 


19 


13 


Julv 31 


22 


14 


Aug. 3 


20 


15 


Aug. '• 


2> 


16 


Aug. 9 


44 


17 


Aug. 12 


!l 


Is 


l.ug. 15 


.., 


19 


\UL'. Is 


99 


20 


\.ig. 21 




21 


Aug. 21 


12 


22 


VUg. 27 


49 


23 


Aug. 30 


67 



Pm „ Emer- Num- 

™* gence ol beroJ 

", ,, para- win- 

":',;'• "-. taring 

"""• 1911. larva?. 



No. of 

record. 



Date of 
collect- 
tag. 



Sept. 2 

Sept. s 

Bept. 11 

Sept. M 

Sept. 17 

Sept. 2o 

Sept. 29 

Oct. 2 

Oct. 5 

Oct. s 

Oct. II 

Oct. 14 

Oct. 17 

Oct. -'ii 

Oct. 23 

Oct. 26 
Oct 



Num- 
ber of 

larva-. 



29 



Total 



Emer- „' „ , f 
gence offe. * 
■noths, 

1911. 



1911. 



It' 



Num- 
ber Of 

win- 
tering 
larva-. 



67 
53 

37 

32 
24 
15 
16 

s 

4 
4 
3 
4 

•"■ 
5 
4 
•"> 

1 
1 



62 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



The results from the above band records are presented in Tables 
LXIII and LXVIII, in so far as same could be completed in 1911. 
The time of appearance of larvae and their relative abundance in the 
respective localities have been graphically shown by curves in figures 
18 and 19. It will be noted here that there is practically no differ- 
ence in the time of appearance of the first larva? in the five localities; 
nor is there any difference in the time of appearance of the earliest 
second-brood larvae, so far as this could be determined. In account- 
ing for this uniformity in time of maturity of larvae it should be 
remembered that the seasonal conditions during 1911 were quite 




Fig. 17. — Mailing case used for shipping codling-moth larvae. (Original.) 

unusual. The spring opened up suddenly and uniformly over the 
entire fruit belt, and the prevailing high temperature must have 
started the development of the insects more or less at the same time 
in the different sections. During 1910, it will be recalled that in these 
localities a slight difference was observed in the time and rate of 
appearance of the first brood of larvae and practically no difference 
in the time of appearance of the second brood of larvae. We may 
deduce from these observations that the seasonal development may 
in years become more uniform in the different sections of the fruit 
belt than is generally the rule, and that these differences are more in 
evidence during the early spring than during the rest of the season, 
while at midsummer conditions are more or less uniform for the 
whole belt. 



TIIK CODLING MoTU IX MICHIGAN. 



63 



Table LXV. — Band records at New Richmond, Mich., 1911; larvae collected by G. W. 

Tibbits. 



XT „ „ f ]>;ilc of 

N "'' collect- 
record. ing _ 


Num- 
ber of 
larva;. 


Emer- 

moths, 
1911. 


Emer- 

p r-.i- 

sites, 
1911. 


Num- 
ber of 
win- 
tering 
larva;. 


No. of 
record. 


Date of 
ij 
ing. 


Num- 
ber of 
larva;. 


Emer- 
ge ice of 

mol b . 
urn. 


Emer- 
gence of 

! n. i- 

1911. 


Nuni- 
i er of 
win- 
tering 
larva;. 


1 June 25 

2 June 28 

3 July 1 

4 July 4 

5 July 7 

6 July 10 

7 July 13 
S July 16 
9 July 19 

10 July 22 

11 July 25 

12 July 28 

13 July 31 










24 

■:, 
-'i. 
27 
28 
2.1 
30 
31 
32 

:;i 
35 
36 
37 
38 
39 
4(1 
41 
12 
43 
11 


Sept. 2 
Sept. •". 
Sept. 8 
Sept. n 

Sept. 1 1 
Sept. 17 

Sept. 2(1 

Sept. 2:; 
Sept. 26 
Sept. 29 

Oct. 2 

Oct. 5 

Oct.. 8 
Oct. li 

Oct. 1! 
Oct. 17 

Oct. 2(1 

Oct. 23 
Hi. 2 
Oct. 29 
Nov. 1 


7 
12 

12 
12 
11 
14 
11 
16 
11 
4 
4 
3 
5 
4 
4 
1 
3 
1 
1 

1 






7 

12 

12 


12 
8 

if 

IX 

17 
21 
10 
19 
17 

5 
9 
14 
11 
20 
14 
12 
12 
13 
10 
11 


11 

2 
2 
10 

111 

5 
7 

1(1 
11 
5 
4 


1 


i 

4 














1 






12 


4 
I 

1 


4 
12 
14 


7 
11 

■> 

5 

4 
12 

8 
17 
11 
12 
12 
13 
11) 
11 






11 




14 




11 

10 
11 
4 
4 
3 
5 
4 
4 
1 
3 
1 
1 
1 












14 
15 
16 
17 

l'l 
20 

L'l 
2' 
23 


Aug. 3 
Aug. 6 
Auk. 9 
Aug. 1.' 
Ail}:. 1"' 
Aug. 18 
Aug. 21 
Aug. 21 
Aug. 27 
Aug. 30 


5 
■> 
3 
3 












































Total 


. 






434 


90 1 9 


335 






\ 



The band-record curves in figures 18 and 10 arc of further interest 
in that they show a marked irregularity in the rate of appearance 
of larva 4 in the different orchards, and none of the curves show any 
natural demarcation between the two broods of larvae which could he 
used as a basis to separate the two broods. 

Table LXVI. — Band records at the lake shore near Douglas, Mich., 1911. 



No of Dateof 



June 25 
June 28 

July 1 
July 4 
5 J ul y 7 
o Juh lo 
7 July 13 
s July H. 
9 July 19 
10 I July 22 



July 25 
July 28 
July 31 
Aug. :: 
Aug. 6 
Aug. 9 
A.Ug. 12 
Aug. 15 
Aug. 18 
Aug. 21 
Aug. 2! 
Aug. 27 
All-. 3' i 

Sept. 5 



Num- 
ber of 
larva;. 



T? m =» Emer 

moths, 

loi i > 

i.ui. igil 



o 
12 

11 

11 
57 
23 

19 

2.1 

1' 

18 

- 

43 
44 
43 

5.1 
44 
53 



Num- 
ber of 
win- 
tering 
larv c. 



No. of 
record. 



I »ate of 
collect- 
ing. 



- pt. x 

Sept. li 
Sept. n 

-•i Sept. 17 
30 Sept. 20 
;i B ipt. 23 

32 Sept. 26 

33 Sept. 29 

34 oo. 2 
.15 Oct. 5 

»l I. s 
Oct. 11 
Oil. 11 

Oct. 17 
Oct. 20 
Oct. 23 
Oct. 26 
ii.i. 29 
Nov. 1 
Nov. 4 
Nov. 7 
Nov lo 



tt„,„ Emer- 

berof V ,'V., para- 
larva;. " ; ' ■ 

1911. 



Total 1,125 



Num- 
ber of 

win- 
tering 
larva;. 



829 



6-1 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Some of the band records might even become misleading were 
(hey not supplemented In" observations from the rearing experi- 
ments. For instance the great drop in the curve of the Benton 
Harbor record (fig. 19) was due to the exposed condition of the 
apple trees and to severe storms during the latter half of July. Owing 
to the dropping of over half of the apple crop that resulted, a large 
number of larvre failed to reach the bands, and many immature larvae 




Fig. is. -Curves made from baud-record experiments in orchards at the lake shore near Douglas, at Douglas, 
and at New Richmond, Mich. , 1911. (Original.) 

were materially delayed in their normal growth in apples on the ground. 
There is also to be noted a marked difference in the relative abund- 
ance of first-brood and second-brood larva? in the different localities. 
Of the total number of larvae of the Douglas band records 50 per 
cent were of the second brood, while of the Pent water records only 
31 per cent pertained to the second brood. For a comparison of 
the details of the results for the five band records reference is made 
to Table LXV1II. 



THE CODLING MOTH IX MICHIGAN. 



65 



Table LXVII. Band records of 1911, at Pentwater, Mich.; larva collected by S. •/. 

Taylor. 



No. of 

record. 


Dateol 
collect- 
ing. 


Num- 
ber of 
larvae. 


Emer- 

Kcncc of 

L911. 


Emer- 
gence ol 
para- 
sites, 
1911. 


Num- 
ber of 
win- 
tering 
larva?. 


No. of 
record 


1 lulc of 

collect- 
ing. 


Num- 
i ei of 


Emer- 
gence of 

1911. 


gence of 
para- 
sites, 
1911. 


Num- 
ber of 

win- 
Ic-iillK 

larvae. 


l 

2 

:; 


June 25 

June 28 
Julv 1 


6 
10 
56 
24 
18 
17 
37 

41, 
57 
73 
38 
1 
52 
45 
38 

If, 
42 
28 
■ 26 
17 
25 
26 
25 
15 
L6 


1 

5 

41 

9 

11 

4 

31 

34 

38 

(.7 

29 

..1 

25 

21 

11 

5 

_' 

4 


2 


5 

5 

10 
15 

7 
13 

G 


27 
28 
29 
30 
31 

33 

34 
35 

37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 

IS 

(9 

50 

T 


Sept. 11 
Bept. 14 
Sept. 17 
Sept. l'ii 
Sept. 23 
Sept. 26 
Sept. 29 
Oct. _' 
i )ii . 5 
Oct. 8 

Oct. 11 

Oct. 14 
Oct. 17 

Oct. -'ii 
Oct. 23 
Oct. 26 
Oct. _"i 
Nov. 1 
Nov. 4 
Nov. 7 
Nov 10 
■Nov. 13 
Nov. 16 
Nov. 19 

otal 


L8 
12 
11 
16 
17 
22 
23 
13 
10 
5 
13 
11 
22 
15 
2 
3 
2 


1 



1 

1,044 






is 
12 

14 

I,. 

17 
22 
23 
13 

lu 
5 
13 
11 
22 
15 
-' 
3 
_' 


1 




1 










4 Julv -1 

5 July 7 

6 July io 

7 Julv 13 

8 July 10 

'.1 Julv 1!) 

10 Julv 22 

11 1 Julv 25 

12 Julv 28 

13 Julv 31 


















12 

l'J 










6 

'.» 
8 
27 
24 

-'7 
-'7 
14 

■ 

28 
26 
17 
25 
26 
25 
15 
16 
















14 
15 
16 
17 
18 
19 
20 
21 
22 
23 

L'4 

25 


Aug. 3 
Aug. 6 

Au K . 9 
Aug. 12 
Aug. 15 
Aug. is 
A uj.'. 21 
Auk. 24 
Auk. 27 
Auk. 30 
Sapt. 2 
Sept. 5 
Sept. 8 










































































2 


670 









Table LXVIII.— Band records of 1911; summaries of Tables LXIII-LXVII. 





Douglas. Lake shore. S Z^" 


Benton 

Harbor. 


Pentwater. 


Aver- 


< ibservations. 


Total 
num- 
ber. 


Per 
cent. 


Total 
num- 
ber. 


Per 
cent. 


Total 
num- 
ber. 


Per 

cent. 


Total 
num- 
ber. 


Per 
cent. 


Total 
num- 
ber. 


Per 

cent. 


age per 
cent. 


Larva? collected from 


.-,17 
91 
19 

261 

in 
170 
250 

407 


LOO.O 


1.125 


25. •", 
.8 

• 

37.0 

,.; 

31.1 

73.7 


134 
SO 

208 

17s 
166 

335 


100.0 

20.7 

2.1 

61.7 

33.6 
66.4 

■ 

77.2 


1,567 

441 
35 

1.008 

411 

567 

559 

1,091 


100.0 

28.1 

2. 3 

64.3 

13. 7 

56.3 
35. 7 

69.6 


1,044 
372 

2 

717 
372 
345 

327 

670 


100.0 
.2 
68.7 
51.9 
48.1 
31.3 

64.2 


100.0 


Mot lis emerging, 191 1 . . 
Parasites emerging, 191 1 
Larva of the Brsl 


17.6 287 
3.7 9 

50.5 775 


25.5 

1.8 

62.8 


Transforming larva; of 




287 


40.0 


Wintering lai 


65 l 
49.5 

78.7 


488 
350 

829 


60.0 


Larva; of the second 


37.2 


Wintering larva; of 

first and second 


72 7 







The averages for the different observations show that from the 
total number of larva' only 25.5 per cent transformed and issued as 
moths in 1911; adult parasites issued in 1911 from 1.8 per cent of 
the codling-moth larva': 62.8 per cent of the larva' were of the first 
brood and .17.2 per cent of the second brood ; of the first-brood larvae 
in per cent transformed and 60 per cent wintered: of both the first 
and second broods 72.7 per cent of the larva? wintered. 

SUMMARY OF SEASONAL-HISTORY STUDIES OF 1911. 

The prevailing high temperature of the season produced a marked 
shortening in the time of development of the codling moth. The 
deviation from the average conditions is only slightly noticeable 
within the separate stages, but becomes strikingly marked for the 



66 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



whole life cycle. Thus the time of hatching of the earliest larvae of 
the second brood came 21 days ahead of those for the previous year, 
and the time of hatching of the second-brood larvae extended over an 
unusually long period of two and a half months. The second-brood 
larvae were exceptionally abundant, being in some orchards equal in 
numbers with those of the first brood. In figure 20 a summary is 
given in a graphical form to illustrate the progress of the development 
of the codling moth in the course of the whole season of 1911. 




30 5 10 |5 2.0 23 30 5 10 15 20 25 30 5 10 15 20 2 
JULY AUGUST 5EPTEMBE 



5 JO 5 10 15 20 25 30 5 10 15 
F? OCTOBER NO V. - 



Fig. 19. — Curves made from band-record ex] eriments i:i en bards s.1 Pentwater, Douglas, and Benton 
Harbor, Mich., 1911. (Original.) 

WEATHER RECORDS FOR 1909, 1910, AND 1911. 
Considering the variation in the time of transformation of the cod- 
ling moth during the three years of observation, it becomes evident 
that the insect is largely governed by climatic conditions. This is 
only natural, since phytophagous insects, depending upon the 
development of their host plants, must to a certain degree be 
governed by the same phonological laws that govern these plants. 
The earliest codling moths of the spring brood generally appear at a 



THE CODLTNG MOTH IN MICHIGAN. 



67 



time shortly after the blooming period of apple, so that the early lar- 
vae will hatch after the setting of the young fruit. A full considera- 
tion of climatic conditions during the years 1909, 1910, and 1911 is 
therefore given for a better interpretation of the life-history studies. 



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A self-recording thermometer of the type generally used by the 
United States Weather Bureau was kept in the rearing shelter 
throughout the seasons of 1910 and 1911. and the records of the tem- 
perature conditions are given in Tables LXIX and LXX in degrees 
Fahrenheit. The average daily temperature in these tables repre- 
sents the averages from hourly readings for each day. The readings 



68 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

of maximum and minimum degrees of temperature were taken from 
a special maximum and minimum instrument. Daily record was 
also kept on the general weather conditions. For the preparation of 
the following account of climatic conditions the writer has in addition 
made ex tensive use of the reports of the United States Weather Bureau. 

The season of 1909 was characterized by a cool and wet April, 
by heavy rains during July, and by an exceptionally warm Novem- 
ber. During the month of May rather cold and dry weather pre- 
vailed. During June the temperature as a whole was seasonable, 
although there were an unusually large number of rainy days. The 
temperature for July averaged slightly below normal, and the pre- 
cipitation was far in excess of normal. During August the tempera- 
ture averaged several degrees above the normal and the rainfall was 
slightly in excess in the southern parts of the peninsula. September, 
on the contrary, was marked by a somewhat low temperature and a 
deficiency of precipitation, October was unseasonably cool and rather 
dry, while November as a whole was unusually warm. 

The spring of 1910 in many of its features was unprecedented, as 
is well stated by the United States Weather reports for March: 

The excessive warmth, the extreme dryness both as regards precipitation and rela- 
tive humidity, the large number of clear days with bright sunshine, the early disap- 
pearance ni snow and ice, the light wind movement, and the absence of serious storms 
makes a history for the month (March) without parallel since the beginning of the 
official records. Never since the Weather Bureau was established has there been such 
an early opening spring. As a whole, the conditions that prevailed at the close of 
the month were those usually experienced from three to five weeks later. 

The warm weather of March continued through the first two weeks 
of April, when many deciduous fruit trees were out in full bloom. 
Following this warm weather, at a very critical period for the 
orchards, a drop of temperature occurred, which was accompanied 
by a storm with rain and snow and severe freezing. The cool weather 
which prevailed during the latter half of April continued with slight 
interruption throughout the month of May and the first half of June. 
Vegetation was not merely greatly retarded, but badly damaged, and 
the season was exceptionally backward. In striking contrast to this 
low-temperature condition came warm weather, which was rather 
above normal, extending over the latter half of June and all of July. 
August was fairly normal. During these last months precipitation 
was below (lie average, and clear bright weather prevailed mostly 
throughout. The weather conditions during September and October 
were fairly normal. A marked drop in temperature set in during 
late October, which brought most insect activity to a standstill for 
the rest of the season. The month of November, in striking contrast 
with 1909, was cloudy and cold. 

The uniform spring of 1911 was very favorable for the development 
of fruit and leaf buds, which were not unduly forwarded. The 
weather during April was rather more severe than usual until the last 



THE CODLING MOTH IX MICHIGAN. 



69 



week of the month, when a pronounced warm spell set in, which 
advanced rapidly the growth of vegetation. The mean temperature 
for May was decidedly above normal, and an abundance of sunshine 
prevailed. The United States Weather Bureau pronounced the heal 
for the month unprecedented. Thunderstorms were frequent , accom- 
panied by high winds and excessive rainfall. This weather condition 
continued without interruption throughout the greater part of June, 
when severe storms occurred, which caused great damage to orchards 
and the fruit crop. During the period from the 11th to the 18th, at 
the height of the emergence period of the spring brood of moths, a 
markedly low temperat ure prevailed, accompanied by frequent rains, 
which caused a sudden and prolonged delay in the appearance of the 
moths. The weather conditions during July were also very excep- 
tional. The first week of the month was marked by excessive heal 
and great dryness, while during the latter half of the month decidedly 
cold weather prevailed, with frequent local showers. August in most 
respects was normal, while September was marked by sharp alterna- 
tion of warm and cold periods and a frequency of rainfalls. During 
October, and particularly during November, cool weather prevailed, 
which delayed considerably the time for the maturity of many 
second-brood codling-moth larvae. 

Table LXIX. — Temperature records taken in the outdoor rearing shelter, showing maxi- 
mum, minimum, and average daily temperatures, Douglas, Mich., 1910. 





April. 


May. 


June. 




uly. 


August. 


September. 


October. 


November. 




d 


a 
| 

g 




S 


a 




a 


a 




a 


a 




Ej 


a 




a 


a 




E 


a 




E 


a 




3 


| 


s 


| 
m 


B 

a 

'3 




3 
8 
'H 


1 


o 
g 


3 

g 
'H 


3 

a 

3 


CD 
M 
C3 

s 


3 

a 

03 


9 

E 


60 

U 


| 


- 




3 

1 

- 


1 


u 

s 


s 
S 
B 

a 


E 


E 

<D 


Q 


a 


a 


<; 


a 


a 


"" 


a 


a 


< 


a 


a 


< 


'- 


a 


"*< 


s 


a 


<^ 


"^ 


~ 


■*1 


~. 


a 


""• 




"F. 


"F. 


C F. 


"F. 


°F. 


'F. 


■ F. 


°F. 


"F. 


°F. 


°F. 


°F. 


-F. 


°F. 


~F. 


°F 


F 


°F. 


"F 


"F 


'F. 


>F 


°F 


°F. 


1.. 


61 


39 


19. 9 


64 


■is 


54.5 


51 


41 


45.2 


87 


59 72. 5 


74 


56 68. 2 


7(1 


.-,li 


59. 5 


65 


41 


58.0 


50 


38 46. 9 


2.. 


71 


42 


55.7 


54 


43 


50.5 


46 


39 


B. 5 


94 


61 77.0 


80 


62 69. 3 


74 


46 


61.5 


66 


44 


55. 6| 42 


34 37. 4 


3.. 


.is 


48 


59. 


54 


40 


45.3 


54 


42 


16. 7 


81 


62 71-1 


78 


66 72. 5 


72 


62 


66.4 


S3 


5s 


68.2 H 


2s 35. 5 


4.. 


72 


59 


65.0 


49 


36 


43.4 


64 


47 


56.0 


80 


58 69. 


71 


50 65.2 


67 


60 


64.0 


66 


63 


64.5 46 


2633. l 


5.. 


71 


50 


64.6 


53 


33 


43.8 


58 


44 


51.8 


86 


54 70. 4 


72 


50 63.3 


72 


64 


70.4 


72 


57 


65.0 40 


32 36.0 


6.. 


58 


33 


44.1 


58 


33 


47.7 


56 


43 


47.1 


82 


62 72. 6 


74 


48 62. 2 


73 


60 


67. 4 


57 


39 


17.7 32 


30 30. 2 


7.. 


41 


30 


36.0 


60 


38 


53 ii 


57 


44 


19. '.• 


77 


60'b9. 6 


75 


56 64.6 


81 


54 


69.0 


62 


31 


17.8 46 


3137.0 


8.. 


69 


29 


51.2 


53 


46 


49.9 


67 


42 


56 it 


88 


58 76. 6 


7!' 


54 66.9 


75 


61 


68. 6 


61 


111 


53. 8j 46 


34 37. 


9.. 


59 


43 


49.7 


60 


41 


49.5 


74 


53 


63. 7 


89 


6574.2 


74 


64 69.6 


60 


42 


54. 6 


;,s 


41 


51.7 


50 


40 48. 5 


10.. 


71 


38 


56.2 


till 


III 


50.5 


73 


50 


62. 2 


7-1 


65 68.7 


72 


56 67. 2 


64 


39 


52.9 


58 


36 


49.0 


11 


30 37.0 


11.. 


58 


35 


50.0 


54 


36 


11. 8 


66 


50 


56. 1 


81 


67 73. 4 


77 


51161.2 


77 


43 


62.5 


66 


54 


61.2 


36 


30 32. 7 


12 


. r >7 


32 


12. 2 


48 


32 


42. 6 


70 


46 


60 ii 


78 


64 (59. 6 


82 


52 67. 9 


74 


50 


60. s 


60 


1253. 1 


38 


34 30. 


13 


59 


29 


15.0 


47 


34 


40.9 


78 


53 


(ii. ii 


76 


56 67. 


81 


59 70. 1 


61 


16 


53. 6 


69 


40 53.0 


39 


33 35. 2 


14.. 


76 


41 


60 2 


53 


29 


41. S 


76 


52 


65.6 


82 


58 71.7 


7S 


60 68.7 


64 


15 


54.5 


71 


52 60 I 


33 


30 31.4 


15.. 


n 


61 


67. 2 


65 


37 


51.5 


73 


54 


1,1.7 


82 


lis 75.1 


SI 


63 73. 4 


70 


43 


56. 7 


61 


50 55.2 


34 


31 32.9 


16 


74 


39 


5S. 9 


70 


46 


5S.0 


Ml 


55 


69. 8 


82 


ill 72.' 


80 


68 72. 6 


72 


47 


59.4 


7:; 


5864.3 


33 


2830 7 


17 


52 


37 


43. 1 


58 


47 


53.6 


80 


67 


73. 1 


77 


5S 67. 7 


80 


64 72. 3 


66 


52 


60. 3 


7s 


52 62.0 


30 


2828 2 


18 


42 


34 


38 


62 


46 


54.3 


80 


62 


711. 1 


76 


53 63. ' 


74 


59 68. 


71 


55 


63. 7 


81 


5364.9 


31 


29 30. 


I!) . 


45 


39 


40.9 


71 


52 


61.3 


74 


60 


lis 3 


76 


5164.0 


76 


53 63.9 6* 


53 


57. 7 7s 


5866.9 38 


2 1 29. 1 


20. 


48 


3s 


43.7 


68 


51 


61.0 


71 


60 


67. s 


77 


56 69. 8 


74 


55 66.0 67 


50 


60.2 57 


4650.4 13 


23 32. 4 


21.. 


62 


34 


16. 9 


77 


54 


62 3 


s7 


05 


76. 6 


79 


65 72. : 


- 


60 73.4 74 


19 


59.5 53 


46 19. 1 36 


3033.0 


22 


66 


39 


53 I 


74 


52 


62. 4 


86 


66 


75.5 


76 


66 68. 5 


83 


70 76.0 72 


45 


59.3 52 


Hi is. v 


HI 


3034.8 


23. . 


37 


31 


32. 8 


62 


45 52. 8 


v,: 


72 


75.7 


84 


66 74.2 


78 


63 70.7 66 


57 


60.0 61 


39 18.4 


17 


• 


24 


43 


32 


37. I 


58 


4552.3 


84 


60 


73.3 


80 


64 70. 8 


82 


73 76.9 68 


7,7 


60.4 62 


45 53. 9 


42 


3438 ii 


25.. 


42 


36 


38 9 


56 


43 IS. ;, 


84 


55 


ii'.i..-, 


79 


62 71.1 


7s 


58 68.4 57 


(8 


54.7 58 


1050. 1 


in 


3036 i 


20. . 


57 


36 


14.2 


50 


42 16. 2 


81 


55 


70.2 


85 


59 73. 4 


68 


50 60.4 65 


45 


57.1 


61 


44 51.1 


14 


24 33. 2 


27 


.'.I 


40 


45. 6 


60 


39 50. 4 


71 


61 


67.8 


77 


04 70. '. 


71 


48 60.8! 58 


53 


55. 1 


:,i 


34 IJ.i 


:;s 


32 31. 1 


is!; 


63 


42 


53.5 


74 


40 


62. 1 


7s 


53 


till. •> 


82 


59,70. S 


75 


53 64. 1 64 


43 


52 ' 


34 




3i 


32 33. 3 


29 


71 


56 


65. 2 


62 


Hi 


54.5 


80 


56 


69 '. 


80 


61 72. 8 


76 


5867.0 6i 


12 


55. i 


X 


30B1. s 


31 


28 29. 8 


30 


56 


44 


17.7 


17 


43 


45.0 


83 


60 


72. 3 


72 


6ii r,7.: 


81 


6070.4 72 


51 


64.0 


52 


29 13 1 


33 


2830.3 


31 








42 


40 


41.0 








7-. 


48! 62. a 


7' 


59 66. 3 1 






5S 


32 17 1 




























1 




1 







Note.— The records from Apr. i to 20, Inclusive, were taken from Mr. Tillinghast's records al Douglas, 
Mich. 



70 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table LXX. — Temperature records taken in the outdoor rearing shelter, showing maxi- 
mum, minimum, and average daily temperatures, Douglas, Mich., 1911. 





May. 


June. 


July. 


August- 


Septeml >er. 


October. 


November. 




a 


A 




d 


H 




a 


B 




s' 


a 




a 


a 




a 


a 




d 


j 










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p 


o 


3 


3 


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2 




m 


p 


^ 




3 


3 

a 

3 


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p 




o 


6 

c3 


a 

03 


g 

'5 


03 
Eh 

CJ 

> 




03 


a 

3 


to 

m 

o 
> 


H 

03 


6 

3 


to 

03 
3 


S 
03 


| 

'3 


So 

03 
OJ 


a 

H 

03 


a 


So 

03 

frH 

0) 


03 


03 
H 


a 
s 

03 


a 

'a 


to 

03 

u 

a 


Q 


a 


S 


< 


a 


a 




a 


a 


< 


a 


a 


•o* 


a 


a 


< 


3 


a 


<} 


a 


a 


< 




°f. 


° F. 


°F. 


"F. 


"F. 


°F. 


°F. 


°F, 


°F. 


F 


" F. 


"F. 


° F. 


° F 


"F. 


° F. 


° F. 


"F. 


"F. 


° F 


"/'. 


1... 


58 


32 


41.5 


70 


49 


61.0 


89 


67 


79.2 


76 


66 


70.8 


83 


55 


69.5 


54 


50 


51.8 


41 


2S 


35.3 


2... 


44 


33 


36.5 


69 


48 


63.0 


89 


75 


80.8 


73 


59 


66.2 


77 


54 


67.1 


60 


46 


52.7 


33 


25 


29.7 


3... 


52 


35 


42.9 


80 


60 


66.9 


92 


73 


81.2 


76 


55 


66.3 


70 


49 


59.8 


69 


44 


54.0 


41 


30 


34.2 


4... 


59 


38 


43.3 


84 


62 


70.8 


94 


88 


83.1 


81 


63 


70.2 


81 


47 


65.2 


60 


49 


55.4 


40 


31 


35.9 


5... 


59 


31 


43.6 


75 


52 


65.2 


95 


78 


86.0 


85 


69 


73.7 


75 


61 


65.7 


50 


37 


46.7 


48 


38 


41.8 


6... 


72 


26 


51.9 


70 


59 


63.2 


79 


68 


73.7 


86 


61 


74.3 


63 


59 


60.8 


62 


46 


52.3 


50 


42 


49. 5 


7 ... 


74 


43 


59.7 


68 


54 


60.8 


85 


65 


71.4 


88 


64 


77.0 


73 


57 


62.2 


55 


36 


46.0 


44 


40 


41.8 


8... 


75 


51 


61.3 


75 


53 


65.9 


89 


65 


78.9 


74 


69 


69.4 


70 


56 


67.9 


56 


31 


44.5 


50 


33 


40.2 


9... 


76 


55 


62.4 


84 


62 


75. 3 


89 


73 


79.7 


84 


57 


70.7 


64 


53 


60.1 


63 


38 


49.6 


47 


33 


41.3 


10... 


82 


54 


68.9 


86 


67 


74 9 


89 


73 


77.2 


87 


62 


73.1 


71 


53 


61.9 


60 


48 


52.7 


59 


48 


52.4 


11... 


64 


55 


60.3 


78 


64 


66.2 


87 


71 


78.2 


78 


64 


67.4 


73 


58 


64.9 


60 


46 


52.0 


72 


46 


62.4 


12— 


68 


42 


52.5 


64 


53 


59 2 


78 


60 


67.1 


73 


57 


65.3 


62 


52 


55.4 


59 


43 


50.0 


39 


120 


'23.1 


13.. 


65 


36 


48 5 


66 


51 


58.8 


78 


59 


70.8 


78 


60 


67.0 


67 


48 


56.3 


64 


42 


51.9 


25 


120 


'23.2 


14.. 


75 


47 


61.4 


72 


53 


61.2 


79 


68 


69.1 


81 


67 


73.4 


70 


50 


60.6 


59 


48 


53.2 


33 


24 


27.2 


15.. 


79 


55 


68.7 


72 


53 


63.3 


82 


57 


70.6 


76 


67 


69.6 


72 


61 


66.2 


63 


47 


53.0 


34 


20 


3a 4 


16.. 


79 


58 


68.8 


68 


60 


63. 4 


72 


63 


65.7 


81 


69 


73. 3 


73 


50 


62.8 


76 


50 


63.1 


34 


21 


27. 


17.. 


79 


64 


71.9 


69 


60 


62 3 


72 


54 


61.9 


77 


67 


70.9 


82 


53 


68.5 


57 


42 


53.7 


48 


30 


35.5 


18.. 


84 


64 


74.7 


73 


55 


63 7 


79 


54 


68.4 


78 


63 


66. 3 


74 


61 


66.7 


64 


41 


53.3 


34 


26 


2S. j 


19.. 


86 


72 


79.2 


78 


55 


68.1 


75 


64 


67.7 


69 


51 


60.0 


64 


48 


59.2 


54 


46 


50.2 


32 


27 


29! 8 


20.. 


85 


59 


70.0 


76 


62 


69.5 


77 


53 


66.4 


70 


49 


60.9 


IIS 


45 


57.9 


53 


45 


47.9 


34 


28 


31. & 


21.. 


74 


61 


69. 8 


79 


55 


70.1 


72 


64 


66.0 


80 


53 


68.5 


6S 


47 


56.3 


51 


43 


45.9 


34 


28 


31.3 


22.. 


76 


60 


65.0 


85 


65 


76.9 


75 


53 


68.0 


72 


66 


65.3 


70 


44 


56.2 


48 


42 


44.3 


37 


28 


33.0 


23.. 


70 


60 


61.4 


87 


67 


77.3 


76 


56 


63.7 


71 


51 


59. '.) 


72 


50 


62.4 


46 


42 


44.5 


38 


28 


32.6 


24.. 


72 


54 


58.0 


82 


59 


69.7 


68 


53 


59.6 


70 


56 


59.3 


67 


59 


62.0 


51 


41 


45.3 


31 


26 


28.0 


25.. 


82 


57 


70.3 


80 


69 


73.1 


66 


53 


59.8 


72 


45 


57.9 


60 


50 


56 9 


57 


41 


47.4 


39 


30 


34.7 


26.. 


82 


63 


72.1 


83 


68 


74.9 


71 


51 


62.3 


78 


49 


63.4 


63 


43 


53.9 


50 


32 


39.1 


48 


34 


38.4 


27.. 


89 


64 


78.2 


77 


67 


68.6 


77 


49 


64.2 


79 


59 


68.5 


68 


47 


61.0 


44 


30 


35.3 


47 


32 


38.6 


28.. 


lis 


61 


62.9 


64 


58 


60.3 


78 


56 


69.2 


69 


59 


62.7 


63 


42 


54.2 


47 


33 


40.7 


3S 


26 


33.6 


29.. 


74 


55 


64.5 


74 


48 


63.1 


78 


61 


63.3 


66 


46 


55.7 


62 


47 


53.9 


51 


42 


46.5 


32 


21 


27.7 


30.. 


75 


52 


65.3 


83 


47 


74.3 


82 


62 


73.7 


74 


44 


58.2 


56 


46 


50.6 


48 


41 


43.9 


34 


27 


31.2 


31.. 


67 


58 


60.0 








86 


63 


76.0 


74 


53 


59.5 








44 


38 


40.1 





























Temperatures below 20° F. not recorded. 



COMPARATIVE LIFE-HISTORY STUDIES FOR THE SEASONS OF 
1909, 1910, AND 1911. 

On considering the seasonal variations in the time of transforma- 
tion and the relative abundance of the codling moth it is evident 
that the climatic conditions, and mainly the temperature, are the 
direct governing factors. Sometimes a scarcity of fruit may mate- 
rially reduce the normal abundance of the codling moth. The effect 
of climatic variations upon the life of the insect is particularly 
noticeable in the spring, when the relative earliness of the season is 
followed by a corresponding change in the time of emergence of the 
moths. From the curves of figures 1, 6, and 14, which represent the 
time of emergence of the spring moths for the respective years of 
1909, 1910, and 1911, with temperature records for the last two 
years, it will he noted that under prevailing uniform temperatures 
the emergence for the main portion of the moths becomes limited 
to a short period, as occurred in 1910, while on the other hand unxler 
fluctuating temperatures the emergence is very irregular and extends 
over a much longer period of time, as observed in 1911. 



THE CODLING MOTH IN MICHIGAN. 



71 



The time of the emergence of the earliest moths has closely fol- 
lowed the time of blossoming of apples and occurred from 5 to 10 
days after the blossoms dropped (Baldwin apples). By adding 
to these figures the time of flight of the moths previous to oviposi- 
tion and the time of incubation of the eggs it was found that fully 
three weeks elapsed before the hatching of the earliest larval of the 
first brood. 

In 1909 the moths commenced to appear at a normal time, but 
were somewhat delayed in reaching a maximum of emergence. The 
season as a whole was fairly normal. The late fall, together with 




Fig. 21.— Diagram showing time ol emergence and relative abundance of spring-brood and summer-brood 
codling moths, and blooming period of apple trees, during 1909, 1910, and 1911 at Douglas, Mich. 
(Original.) 

other favorable influences, produced a development of a very large 
second brood of larvae. Of the total number of larva 1 for the year, 
43 per cent were of the first brood and 57 per cent of the second 
brood. This occurrence was perhaps directly due to the unusual 
rate of emergence of the moths of the summer brood. These com- 
menced to appear at the normal time, but already reached a maxi- 
mum during the early part of August (fig. 21) instead of the Latter 
part of the month, which is the general tendency as shown for 1910. 
In the band-record curves of figure 22 is shown a corresponding 
rate in the time of maturity of larvrc of the second brood. The 
maximum in the first brood of larvae occurred comparatively late, 



72 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



which in turn reduced the - percentages of transforming larvae as 
against the percentage of wintering larvae of the same brood (see 
Table LXXI). The occurrence of an early maximum of larva 1 in 
the second-brood larva? was due to the early rate of emergence of the 
moths of the summer brood, and to favorable climatic conditions. 

During 1910 the codling moths of the spring brood were delayed 
in the time of emergence of the earliest individuals. The larger 
number of moths, however, emerged very soon after the first appear- 
ance of moths, so that for the rest of the season the dates for the 
occurrence of the separate stages were about normal. The summer 
moths commenced to appear July 26 and reached a maximum of 



JUME 

5 10 15 20 25 



JULY 

5 10 15 20 25 



AUGU5T 

5 10 15 20 25 



5EPTEMBER 

5 10 15 20 25 



□ETDBER 

5 10 15 20 25 



NOVEMBER 

5 10 15 20 25 




fS/0 



f$ff 





Fig. 22. — Diagram showing time of leaving the fruit by the first-brood and second-brood larvse of the cod- 
ling moth during 1909, 1910, and 1911 , at Douglas, Mich. ( Original. ) 

abundance during late August, which has been observed to be the 
general rate of emergence for the brood. In 1910 the codling 
moth was naturally limited in numbers as a result of the small 
crop of apples, and to this must be ascribed the reduced size of the 
second brood. Of the total number of larva? from the band records, 
73.2 per cent were of the first brood and only 26.8 per cent of the 
second brood. In some sections of the Michigan fruit belt the 
apple crop was so limited that only one brood occurred, the fruit 
having dropped before the second brood developed. 

The spring of 1911 opened at a normal time. The temperature 
during the latter part of May and all of June was on an average 
exceptionally high, and this condition forwarded the development 
of both plants and insects in a very unusual manner. The moths 
commenced to emerge at a normal time, as compared with pheno- 



THE CODLING MOTH IN MICHIGAN. 



73 



logical developments. In the course of the emergence period 
part of the moths of the spring brood were hampered by cold rains, 
which set in during the middle of June and caused a somewhat pro- 
longed delay for about one-half of the moths. This irregularity in 
the development of the insect produced an unusual effect upon the 
tune and rate of occurrence of the separate stages for the rest of 
the season. This is noticeable from a study of the curves of figure 
21 for 1911. In the summer brood there occurred an abundance 
of moths at the very start of the emergence, which was followed 
by a decrease in number as a result of the delay found in the spring 
brood; then again an abundance of moths appeared during the first 
half of August as a result of the emergence of the later half of the 
spring brood of moths. The prevailing high temperature advanced 
the earliest developing insects to the extent that the second-brood 
larva 1 appeared three weeks ahead of those of 1910, and further 
prolonged to a very unusual extent the time of emergence of the 
summer moths, the period of egg deposition, and the period of 
hatching of the second brood of larva 1 . The large fruit crop, together 
with the high temperature, favored the development of a large 
second brood of larva*. For the total number of larvae collected at 
the Douglas band records 50.5 per cent were of the tirst brood and 
49.5 per cent of the second brood. 

Table LXXI. -Summary of results of hand records for 1909, 1910, and 1911, at Douglas, 

Mich. 



( Observations. 



Mollis emerging the same season 

Mnihs emerging the following season 

Total emergence of moths 

Wintering larvae of total band collection. . 

Wintering larva- killed by frost 

Parasitized larva- 

Relative proportion of first-brood larva-... 
Relative proportion of second-brood larva- 

Transforming larva- of first brood 

Wintering larva- of first brood 




50.5 
19. 5 
34.9 
65. 1 



The results from the band records for the three years at Douglas 
show that of the first-brood larva about one-third transformed 
the same season and two-thirds passed the winter in the larval stage, 
as do all second-brood larvae. (Sec Table LXXI.) 



INSECT ENEMIES. 1 
PREDACEOUS INSECTS. 

Several predaeeous insects have been found to attack the larvae 
and pupae of the codling moth. Of these a small black beetle and its 
larva, TenehrohU s corticalis Melsh, (PI. Ill, figs. 4. 5). belonging to 

1 For information relative to the bird enemies of the codling moth, see yearbook of the Department 
of Agriculture for 1911, pp. 199-208, "Bird Enemies of the Codling Moth," by W, i. UcAtee. 



74 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

the family Trogositidae, has been found to constitute one of the most 
important predatory insect enemies of the codling moth. The 
slender and flat form of the larva and also the depressed shape of the 
beetle enable the insect to penetrate into narrow cracks and crevices 
in search of prey. Both the larvae and beetles have been found in 
the cocoons of the codling moth, having penetrated the walls of the 
same and destroyed the host. Full-grown larvae and beetles have 
been collected in the late fall and in the spring, which would indicate 
that the insect passes the winter in both stages. The white and deli- 
cate pupa was once observed under the bark in a small cavity, which 
must have been made by the larvae previous to pupation. 

There are several species of carabid beetles that have been found 
under the bands on apple trees. Of these Pinacodera limbata Dej. 
(PI. Ill, fig. 3) and Platynus placidus Say were seen to destroy the 
larvae of the codling moth. Mr. W. Postiff collected in 1910 one 
specimen of Tenebroides castanea Melsh., which also was destructive 
to codling moth larvae. These specimens were kindly determined by 
Mr. E. A. Schwarz, of the Bureau of Entomology. 

In wind fallen apples the codling moth larvae are sometimes 
attacked by wireworms (species not determined), which have been 
found in wormy fruit. In confinement the wireworm larvae fed freely 
upon codling moth larvae, even after the latter were removed from 
the fruit. 

The larvae of a lacewing fly (Chrysopa sp.) were often obseived in 
the act of absorbing the contents of the eggs of the codling moth. 
In the rearing shelter these insects were regular pests, in that they 
would destroy the eggs in the cages under observation whenever the 
eggs were left exposed. In the orchards the larvae of the lacewing 
flies are very common and no doubt they play there an important 
role in checking the codling moth. 

PARASITIC INSECTS. 

Among the native lrymenopterous parasites of the codling moth 
Ascogaster (Chelonus) carpocapsse, Vier. (PI. Ill, figs. 1, 2) is the most 
commonly observed. It has been collected in the States of Michigan, 
Pennsylvania, Maryland, Virginia, and Nebraska, and will probably be 
found in most localities where the codling moth occurs. The species 
was originally described by Mr. H. L. Viereck * from specimens col- 
lected at Douglas, Mich., in 1908 by Mr. R. W. Braucher. The writer 
also reared the insect in abundance at North East, Pa., in 1908 and 
1 909. The band records in 1 909 at Douglas, Mich., showed that 0.6 per 
cent of the codling moth larvae were parasitized, and in 1910 the sep- 
arate band records showed the following extent of parasitism: New 
Richmond, 7.7 per cent, Saugatuck 4.7 per cent, and Lake Shore 7.25 
per cent. 

i I'nx'. Ent. Sou. Wash., vol. 11, p. 13, 1909. 



Bui. 1 1 5, Part I. Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate III 




Insect Enemies of the Codling Moth. 

Fig. 1. — Ascogaster carpocap83e,a hymenopterous parasite of codling-moth larva\ Fig. 2. — Cocoon 
of Ascogastt r carpoeapsse within a cocoon of the codling moth, enlarged twice. Fit;. :'..—/'///- 
acodera limbaia, a predaceous beetle destructive to codling-moth larvae. Figs, i, 5. — Zfene- 
broides COrUcaiis, beetle and larva, which feed upon the larva and pupa of the codling moth. 
(Original.) 



THE rODIJNC Mol'll IN MICHIGAN. 



,0 



The time of emergence of the adult parasites coincides with the 
time of emergence of the two broods of the codling moth. (Tables 
LXXII andLXXIII.) Like the host, the parasite is evidently two- 
brooded or possibly has a partial second brood. 

Table LXXII. — Time of emergence of tin spring brood and the summer brood of Asco- 
gaster curpocapsx at Doug/us, Mich., 1910. 

SPRING BROOD. 



Number 
oj para- 
sites. 


Date of 
emer- 
gence. 


Number 
of para- 
sites. 


Date of 
emer- 
gence. 


Number 
of para- 
sites. 


Dal si i 
emer- 
gence. 


Number 
of para- 


Date of 
emer- 


■_> 
9 
5 

11 
li) 


June 22 
June 23 
June -i 
June 25 
June 26 


9 

2 

14 

5 
3 


June 27 
June 28 
June 29 
June 30 
July 1 


4 
1 

5 
3 
1 


July 2 1 
July 3 I 

July .1 

July 6 86 

July 8 


July (t 

July L5 



SUMMER BROOD. 



July 26 

July 30 

Auk. 2 

A hi;. I 

Aug. .5 

Aug. 7 

Aug. 8 

Aug. 10 



Aug. 11 

Aug. 12 

Aug. 13 

Aug. 14 

Aug. 1") 

Aug. L6 

Aug. 17 

Aug. 18 



Aug. 19 

Aug. 20 

Aug. 22 

Aug. 23 

Aug. 24 

Aug. 25 

Aug. 26 

Aug. 27 



3 Aug. 29 

1 \u-'. 30 

2 Sept. 5 



Table LXXIII. — Time of emergence of spring and summer broods of A.scogaster car- 
pocapsn at Douglas, Mich., 1911. 



SPRING BROOD. 



Number 

of para- 
sites. 



Date of 
emer- 
gence. 



June 2 
June 5 
June 
June 8 
June 9 
June lo 
June 11 



Number 
of para- 
sites. 



Date of 
emer- 
gence. 



June 12 
June 13 
June 14 
June IS 

June 10 
June 17 
June 18 



Number 
i.l para- 
sites. 



Dale of 
emer- 
gence. 



June 19 
June 20 
June 21 
June 22 
June 23 
June 24 
June 20 



Number 
of para- 



83 



Date of 
emer- 
gence. 



June 28 
June 29 

June 30 









SUMMER 


BROOD 










1 


July 9 


6 


July 21 


5 


Auk. 


4 


1 


Auk. 15 


3 


July 11 


1 


July 23 


1 


Auk. 


6 


2 


Aug. 10 


1 


July 12 


2 


July 20 


1 


Aug. 


7 


1 


Aug. 17 


3 


July 13 


2 


July 28 


4 


Aug. 


8 


1 


Aug. is 


2 


July 11 


■> 


July 30 


2 


Aug. 


9 


1 


Aug. 20 


2 


Juij IS 


a 


July 31 


1 


Aug. 


10 


■? 


Aug. 22 


1 


July 16 


1 


Aug. 1 


2 


Aug. 


11 2 


Auk. 27 
Sept. 3 


1 




2 


Aug. 2 


i 


Auk. 


13 1 


■j 


July 19 


1 


Aug. 3 


.) 


Aug. 


u 

71 





The time and stage of the development when the codling modi 
larvae become parasitized are not definitely known. Probably many 
larva 1 are parasitized alter they leave the fruit and while in search of 
suitable places for the spinning of their cocoons. It is very evident 
that many larvae are parasitized while still in the fruit, since adult 
35215°— Bull. 115, pt 1—12 G 



76 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

parasites have been obtained from codling moth larvae which were 
collected in windfallen fruit and confined in cages. At the time the 
parasitized codling moth larvae leave the fruit they may readily be 
recognized by their inferior size and the absence of the pink color, 
which is characteristic of the full-grown codling moth larvae. In the 
orchard on the grounds of the station, where numerous adult parasites 
had been liberated in the course of the season of 1911, fully 40 per 
cent of the band-record larva? were parasitized in the late fall. The 
average measurement of the head of full-grown codling moth larvae 
is 1.5 mm. : the parasitized larva at the time of leaving the fruit has 
an average head measurement of only 1.3 mm. In the spring of 
1911, 15 undersized larvae, lacking the pink color, were confined in a 
separate cage; of these, 10 proved later to be parasitized, while the 
rest died from other causes. 

The parasite passes the winter in the larval stage within the host. 
The following spring feeding is terminated, and the host larva is 
completely devoured, except for the skin and the ehitinous parts 
of the head. Within the cocoon of the host the parasite larva makes 
a small oval cocoon, white in color, within which it pupates shortly 
after. In 1911 one parasite pupated May 21 and issued as adult May 
28, having remained 7 days in the pupal stage. So far as has been 
observed, only a single parasite develops in each host larva. 

The parasitized codling moth larvae that winter do not modify the 
cocoon in the spring as does the normal larva, which provides an exit 
for the issuing moth. The parasite fly is therefore forced to gnaw its 
way out through the walls of the cocoon. 

NEMATODE WORMS. 

On September 1, 1910, the writer collected a windfallen apple with 
a full-grown codling moth larva which was found to be infested with 
minute, white-colored nematode worms (species not determined). 
The entire body cavity of the larva was filled with the worms and 
quite a number of worms were also found in the burrows in the apple, 
where the mass of worms had the general appearance of mildew 
growth. 

MISCELLANEOUS OBSERVATIONS. 

NUMBER OF LARVAL INSTARS AND MOLTS OF THE CODLING MOTH. 

The codling moth, like all arthropods possessing an exoskclcton, 
must shed the skin from time to time in the course of its growth. 
The process of casting the skin is called "molting" (ecdysis) and 
(he stages between the molls are termed "instars." 

The determination of the number of insfnrs of the codling moth 
1' scomes difficult because <>l the small size of the larva in (lie early 



THE CODLINc; MOTH IN MICHIGAN. 



77 



stages and its habit of feeding within the fruit, where it can not 
readily be located for observation without great care and labor. 
Mr. E. L. Jenne, 1 in his studies of the codling moth in the Ozarks, 
determined the number of molts of the larva3 by rearing them on 
small pieces of fruit in glass vials. The vials were frequently exam- 
ined for the cast skin of the head, and on this basis the number oi 
molts was established. Jenne encountered great difficulty in 
preventing the fruit from rotting and in maintaining the larvae in a 
healthy condition. His records from 12 larvae showed that 9 larvae 
passed through 7 instars and 3 larvae passed through 8 instars. 

At Douglas, Mich., the writer, in determining the larval molts, 
made use of Dyar's 2 method of head measurements, on the basis 
that ''the widths of the head of the larva in its successive stages 
follow a regular geometrical progression." By this method the 
necessity of finding the cast skin was eliminated and the larva; could 
be reared in entire fruit or in large pieces of fruit. On the other hand, 
this practice involved a considerable amount of labor and additional 
difficulties both in the finding of the larva 1 and the taking of the 
measurements. 

Table LXXIV. — Instars of the codling moth larvae of the second brood, and head measure- 
ments in millimeters for each instar, Douglas, Mich., 1910. 



No. of ob- 
bot ration. 



First instar. 



Hatch- 
ing. 



Aug. 11 

Ail?. 12 

.do. 



Aug. 1(> 

..do 

..do 

..<lo 

..do 

Ant;. 20 
..do 



Mn, 



o. 33 
.33 
. :;:; 
. 33 
.33 
.33 
.33 
.33 
.33 
.32 



Second instar. 



First 
molt. 



.Nil-. 
Aug. 
..do. 
Auk. 
..do. 
..do. 
..do. 
..do. 
Sept. 
Sept. 



Mm. 



0.50 
.45 

. 50 
.48 

. .').') 

. 55 
. 46 

.511 
.40 
.48 



Third instar. 



Second 

molt. 



Auk. 
Auk. 
Auk- 
Auk. 
Auk. 
..do. 

m 

Sept. 
Sept. 

Sept. 



Mm. 



Fourth instar. 



Third 

molt. 



0.66 

. 66 
.63 
.66 
.73 

.70 



Auk. 27 

..do 

Sept. 5 

< : > 
( 3 ) 



( 3 ) 

Sept. '_>L> 

Sept. 12 



Mm. 



1.00 
1.03 

1.00 

.9] 



.87 

.Si! 



Filth instar. 



Fourth 
molt. 



Sept. 8 

Sept. 1 
Sept. 1-' 



„ (3) 
Sept. 21 



Mm. 



1.40 



1.30 

1.2(1 



No. of ob- 
servation. 



Sixth instar. 



Fifth 
molt. 



Mm. 



1 

•> 


Sept. 20 


1.60 


3 

1 


Sept. IS 
Sept. 22 , 


1.53 

1.50 


fi 


7 ' 


8 '.. 


9 


10 


(*) 





Pupation. 



Sixth 
molt. 



Se 



Days duration of instars. 



First 

instar. 



Second 

instar. 



Third 
instar. 



Fourth 

instar. 



Fifth 
instar. 



(') 



Sixth 
instar. 



1 Bul. so. Part 1. Bur. Km., ('. S. Dept. Agr., L909. 
- Psyche, vol. 5. p. 420. 
■ Died. 
' Wintered 



78 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table LXXV. — Larval instars of the codling moth; head measurements in millimeters 
for each instar; duration' of instars. Summary of Table LXXIV. 





Head measurements in mm. 
instar. 


per 


Days duration of instars. 






c 










lM 






< ibservations. 


m 


1 




p 


3 


~ 

g 


3 


03 
C 


03 


a 


3) 


03 




c 


•a 


£j 


.s 


e 


H 


rS 


a 




a 


a 






a 


•C 






.d 






•d 


^ 




s. 






























h 




.c 


c 


^ 


.a 


.3 


£ 


ST. 


o 


^ 


* 




Eh 


CO 


* * 


h 


CO 


N 


CO 


Eh 


pq 


N 


CO 


Average 


0. 33 


0.4s 


0.67 0.94 


1 . 24 


1.54 


6.3 


5.7 


7.9 


8.2 


13.0 


(!) 




. 33 

.:i2 


.111 


.::? 1 1.03 


1.40 
1.06 


L.60 
1.60 


J4 
I 


11 
4 


15 

4 


12 


17 
10 


(!) 


Minimum 


.63 


.83 


(') 



1 Winter. 

The head measurements were all made by an ocular micrometer 
of a compound microscope. It was necessary to bring the larvae to 
a perfectly quiet position before the readings could be made. In 1910 
tlxis was accomplished by placing a cover glass over the larvae during 
the early stages. The larger larvae were held in place between two 
broken pieces of glass and by a small glass cover placed above. The 
results of these readings are given in Table LXXIV. Four larvae 
out of 10 reached maturity and entered their winter cocoons. Three 
of these passed through six instars and one larva passed through five 
instars. A summary of these readings has been brought together in 
Table LXXV. The average length of the entire feeding period was 
evidently prolonged beyond that of the normal. The records for the 
minimum length of time of each instar represent more nearly the 
normal. 

In 1911 similar observations w r ere again made for both first-brood 
and second-brood larvae. To quiet the larvae for the necessary read- 
ings they were held over a piece of ice under the microscope. The 
exposure of the larvae to the ice was made as brief as possible and in 
most instances extended to a few seconds. It was found that the 
larvae would resume their normal activities within a minute after the 
exposure, and this treatment seemed to have no material effect upon 
the larvae so far as altering the normal numbers of molts, since the 
results of these tests are identical with those of 1910. 



THE CODLING MOTB IX MICHIGAN. , !) 

Table LXXVI. Observations on tin instars of the first-brood codling-moth larvn at 

Douglas, Mich., 1911. 





Date of hatching and molting, and larval head measurements in millimeter , 


Number 
of obser- 


First instar. 


Second instar. 


Third instar. Fourth instar. 


Fifth instar. 


vation. 


Hatched. 


mm. 


First i mm 
molt. mm - 


Second 

molt. 


mm. 


Third 

molt. 


mm. 


Fourth 
molt. 


mm. 


l 


Juno lit 
...do.... 
June 27 
June 28 
...do 


0.35 

. 35 

..;;, 

.35 
.35 
.35 
.35 
.35 
. 35 
.35 


Juno 2ii 
June 27 
July 3 
...do.... 


n. 16 

.45 
. 50 

.40 


July 1 


0.66 
.65 

.68 
.70 
.60 

.05 
.70 
.65 
.62 
.60 
.70 
.65 
.70 


July 5 0.83 
July 6 .88 


Julv 9 
...do.... 

Julv 16 
July 13 
July 17 
...do. . .. 
July 12 
Aug. 1 


1 10 


■> 


1 30 


:i 


July 6 
...do.... 

July 9 
July 8 
July 9 

do. . . 

July 11 
July 14 
July 15 
July 14 

...do 


July 11 
J ul'y 9 
Jul'v 11 
...do.... 


.90 

i 1.10 

.85 

.85 




4 


1 1 .'ii 


5 


1 15 


(i 


...do 

July 2 
...do.... 
...do 


July 4 

July 
...do.... 


.46 
.46 

.49 


1. 15 
1 30 


8 

9 


July 24 
July 17 


.80 
.81 


1.08 


10 


June 7 


July 10 


.4(i 






11 


July 19 
July 20 
July 18 


1.00 
.89 
1.08 






12 










July 28 


l 19 


13 












14 












July 14 


1 i,u 























No. of 
observa- 
tion. 


Date of hatching and molting, and lar- 
val head measurements in milli- 
meters — Continued. 


Days duration of instars. 


Sixth instar. 


Pupa- 
tion, 

sixth 
molt. 


First Second 
instar. instar. 


Third 
instar. 






Fifth 
molt. 


mm. 


Loft 

fruit. 


instar. 


instar. 


1 


July 13 


1.40 






8 
6 
5 


5 


4 


4 
3 
5 
4 

6 
6 


4 


■) 


Aug. 2 
July 27 
July 23 
Aug. 5 
Julv 27 
Aug. 10 
i Aug. 30 


Aug. 8 
Aug. 4 
Julv 31 
Aug. 12 
Aug. 4 


' 30 


3 


July 20 


1.50 


3 
3 


5 
3 
2 
3 


4 


4 


1 is 




July 29 
July 20 
Julv 29 

Aug. 22 


1.46 

1.46 

1.57 

i 1.19 


12 


6 


6 

4 
4 


4 
3 
3 






1 17 


8 


» 1.29 


> 15 
6 


8 


i >\ 


9 




10 








— - 


3 4 






11 


July 28 
Aug. 6 
July 25 
July 19 


1.51 
1.46 


July 31 


4 
6 
4 






1? 






8 







1.50 


Aue. 4 


Aug. 8 
Aug. 1 






14 


1.50 Julv 27 




g 

















Pays duration of instars— Continued. 




No. of 
observa- 


Sixth instar. 


Total 

larval 

life. 


Remarks. 




Feeding. 


In co- 
coon. 


Total. 




i 












2. . . 










Moth emerged Aug. 21; below average size. 
Moth emerged Aug. 19; below average size. 
Moth emerged Aug. 13: below average size. 
Moth emerged Aug. 2.",; average size. 
Moth emerged Aug. 16; below average size. 




7 


8 


15 


50 
33 
45 

37 


4 




12 


7 
8 


14 

15 


6 










59 


Deformed: died Sept. 9. 


9 








10 










Died Julv is. 


11 


'3 








Died before pupation. 

Moth emerged Aug. 21: normal size. 

Died Aug. 20. 

Moth emerged A.ug. 12; normal size. 


12 






13 


10 
8 


4 14 

5 13 




It 









' Abnormal and not included in the summary. 



80 



DF.CTDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table LXXVII. Larval instars of the codling moth; head measurements in millimeters 
for each instar; days duration of instars. Summary of Table LXX VI. 





Head measurements in mm. 
instar. 


per 






Days 


Jural ion of instars. 




























Sixth instar. 


<8 


i tbservations. 




03 




3 








C3 


u> 


CJ 






~ 




3 


.3 
•a 


03 

1 


.9 




3 

.s 


03 

q 


1 




ft 


03 
GQ 

.S 


bi 

3 


3 
O 
O 


a 
3 




.b 


s 
o 
o 


■a 


H 

3 
O 


£ 




.§ 


3 
O 


■a 

2 


O 


3 


0) 


O 

o 


o 




fn 


02 


e- 


fa 


fa 


02 


fa 


02 


Eh 


fa 


fa 


fa 


" 


Eh 


Average 


0.35 


0.47 


0.66 


0.89 


1.16 


1.47 


5.6 


3.6 


4.1 


5.5 


6.1 


8.3 


6.4 


44.8 


Maximum 


. 35 


..50 


.70 


1.08 


1.30 


1.57 


8 


5 


6 


8 


12 


12 


8 


59 


Minimum 


.35 


.45 


.60 


.80 


1.00 


1.40 


3 


3 


2 


3 


3 


7 


4 


33 



In the course of these studies there was a rather high percentage of 
mortality, but this was mainly due to the difficulty in properly remov- 
ing the larvae from the fruit. 

Table LXXVIII. — Instars of the codling moth larvae of the second brood; head measure- 
ments in millimeters; days duration of the instars; Douglas, Mich., 1911. 





Date of hatching and molting, and larval head measurements in millimeters. 


No. of 
observa- 
tions. 


First instar. 


Second instar. 


Third instar. 


Fourth instar. 


Fifth instar. 


Hatched. 


mm. 


First 
molt. 


mm. 


Second 
molt. 


mm. 


Third 
molt. 


mm. 


Fourth, 
molt. 


mm. 


1 


July 29 


a 

S 

CO 

o 


Aug. 2 
Aug. 3 

...do 

...do 

Aug. 7 
Aug. 8 
Aug. 10 

...do 


0.45 
.45 
. 49 
.54 
.46 
.46 
.43 
.49 


Aug. 6 
Aug. 7 
Aug- 8 
Aug. 6 
Aug. 13 
Aug. 15 


0.75 
i 1.00 

.78 
.76 
. 75 
.70 


Aug. 11 
Aug. 12 


0.81 
" 1.22 






2 








...do 

do 






4 










5 


Aug. 2 










6 










7 


Aug. 6 
do. .. 










s 














9 


do .. 










Aug. 18 


10 


Aug. 7 
Aug. 11 
Aug. 12 

...do 

do .... 






Aug. 20 


.66 
.76 


Aug. 27 
...do 


1 1.08 
i 1. 19 


Sept. 2 

Aug. 31 


i 1.51 


11 






i 1.51 


12 


Aug. 20 
A ne. 17 


.50 
.46 
.46 
.50 
• .49 
.49 
.51 






13 


Aug. 25 
Aug. 24 


.68 

.67 










14 


of ...do 

8 Aug. 28 
j; Aue. 26 


Sept. l 


.81 






15 


do 






lti 


do ... 


Aug. 28 
...do 

...do 


.71 
.66 
.67 










17 


Aug. 14 

do.. .. 




Aug. 23 
Aug. 19 
.. do 


Sept. 7 








18 








19 


Aug. 15 

Aug. L6 

Aug. 18 

do 






Sept, 1 


1.19 


20 


Aug. 25 
Aug. 28 
Aug. 25 


.50 
.42 
.46 


Sept. 2 


.67 








21 










22 


Sepl . 2 


.60 










23 


Auk. 24 
do. . 


Sept. 8 
...do 


.80 

.81 


Sept. 15 

Sept. IS 


1.08 


24 










1.08 





















' Abnormal and not included in the summary. 



THE ("OI>UN<; MOTH IX MICHIGAN, 



81 



Table LXXVIII. Instars of the codling moth larva of tJie second brood; head measure- 
ments in millimeters; days duration of the instars; Douglas, Mich., 1911 — Contd. 



No. of 
observa- 
tions. 


Dale of hatching and molting, 
ami larval head measurements 

in millimeters— Continued. 


Days duration of instars. 


Sixth instar. 


I'upa- 
l ion , 

sixth 
moll. 


I" list 

inslar. 


Second 

inslar. 


Third 

instar. 


Fourth 

instar. 


Fifth 

inslar. 


Sixth inslar. 




Fifth 

molt. 


»">'• fruu'. 


Feed- 
ing. 


Winter- 
ing. 


I 










4 
5 
5 
5 

.". 
t! 
4 
4 


4 
4 

.". 
3 
ii 

7 


5 
5 










2 








ti 
ej 

ft 

- 
£ 

ft 


























4. . . 
































li 


































s 
















9 


Auk. 26 


L.81 


Aug. :;i 
Sept. is 

Sept. 10 






s 


5 


(.-) 


in 






7 


6 

1 




11 














12 






8 

.-, 

5 
16 

14 
9 
5 










13 








8 
7 












14... 








S 










1.'). 
















If, 








2 
5 
9 










17 . . 








1(1 










IS 
















19 


Sepl. 6 


1.57 


Sept. is 






5 


12 


(■) 


20... 


9 
10 

7 


8 








21 


















22 








8 












2:! 


Sept. 27 
Oct. 1 


1 62 
1.52 


Oct. 20 
Oct. 18 




7 
111 


12 
13 


23 

17 


( 2 ) 


24 








( 2 ) 













1 Abnormal and not included in the summary. 



- Wintered. 



Table LXXIX. — Larval instars of the codling moth; head measurements in millimeters 
for each instar; duration of instars; summary of Table LXX VIII. 





Head measurements in mm. 
instar. 


per 


Days duration of instars. 


i ibservations. 


- 


— 




JS 

.9 

- 


1-* 


S3 
tfi 


r. 
V. 
C 


03 

7 
c 


"7 


- 


1 


c 
■B 

m 
J) 




*j 


a 

o 


— 




£j 


g 


— 


a 

o 


.= 


H 


.g 


,g 




>- 


- 


« 


■ o 


£3 




.~ 




~ 


O 


!^ 


►j 




fc 


~ 


fc 


fe 


J. 


- 


03 


■- 


fe 


f^ 


cc 




0.35 


.54 

.42 


0.70 
.78 
.60 


0.81 


1.14 


1.63 
l.sl 
1.52 


7 
16 

4 


5.8 

9 

2 


7 
10 
5 


7 
10 

4 


9.5 
13 
5 


11 2 




.81 1.08 
.80 1.22 


23 






5 



















The records for the time of molting and the head measurements for 
the separate instars for the first brood are given in Table LXXVI. 
Of a total number of 14 larva'. 8 attained full growth. Of these. 
2 passed through five instars and 6 through six instars. A single 
larva (No. 8) that appeared stunted in its growth had seven instars. 
but failed to reach maturity. One full-grown larva of this brood 
wintered, while 7 resulted in moths the same year. Larva 1 \<>s. 1 1 to 
14, inclusive, were left undisturbed during their early stages in order 
that their development should not be unduly delayed. 



82 



DECIDUOUS FRUIT tNSECTS AND INSECTICIDES. 



The observations on the. molting habits of the second brood of 
larvae (Table LXXVIII) were not all completed, us at times some of 
the larvae were neglected on account of the stress of other work. 

Table LXXX. — Head measurements of first-brood and second-brood codling moth larvae, 
collected from banded trees at Douglas, Mich., mil. 





First 




Si 'com 1 




First 




Second 


No. of 
larvae. 


brood 

larvae. 

collected 


No. of 
larvae. 


brood 

larvae. 

collected 


No. of 
larvae. 


brood 

larvae. 

collected 


No. of 
larvae. 


brood 

Ian se. 

collected 




July 13. 




Sept. 17. 




July 13. 




Sept. 17. 




m m . 




mm. 




m m . 




m m . 


l 


1.70c? 


1 


1.57 c? 


16 


1.62c? 


16 


1.78 c? 


2 


1.50 9 


2 


1.62c? 


17 


1.83 9 


17 


1.73 c? 


3 


1.56 c? 


3 


1.84 9 


IS 


1.51c? 


18 


1.736" 


4 


1.709 


4 


1.789 


19 


1.S0 9 


19 


1.62 c? 


5 


1.70c? 


5 


1.57 9 


20 


1.62 c? 


20 


1.73 9 


6 


1.62c? 


6 


1.84 9 


21 


1.56c? 


21 


1.739 


7 


1.56 9 


7 


1.689 


22 


1.62 9 


22 


i 


18 


1.299 


8 


1.62c? 


23 


1.67 9 


23 


1.7 


9 


1.62 9 


9 


1.789 


24 


1.02 c? 


24 


1.62 ■ 


10 


1.70 c? 


10 


1.84 9 


25 


1.70 9 


25 


l.S'l 


11 


1.79 c? 


11 


1.68 c? 


26 


1.70 c? 


26 


1.789 


12 


1.56 9 


12 


l.ii.s ' 


27 


1.62 c? 


1 27 


1.27 


13 


1.62 c? 


13 


1.689 


28 


1.62 9 


28 


1.67 c? 


14 


1.5ti ' 


i 14 


1.29 9 


29 


1.80 9 


29 


1.67 9 


15 


1.56 9 


15 


1.73 9 


30 


1.65 9 


30 


1.89 c? 



1 Parasitized larvae. 

The result's from these observations are, however, similar to those 
previously obtained. 

The pink color which is characteristic of the mature larva first 
appeared a few days after the final molt. A number of mature first 
and second brood larvae collected in the field were measured for a 
comparison with those maturing in the laboratory. The records of 
Table LXXX show no material difference in the size of head of the 
larvae of the two sets except that the field larvae are slightly larger, 
which is to be expected, since the latter have developed normally and 
without any 'interference. 

Table LXXXI. — The average widths of the head of the larva in its successive instars and 
the rate of increase at each molt; summary of Tables LX X IV-LX X IX . 



Instars. 


1910, sec- 
ond brood. 


1911, firsl 
brood. 


1911, sec- 
ond brood. 


Average. 


Average 

increase 
at each 
molt. 


First 


17! in . 
0.33 
.48 
.68 
.94 
1.24 
1 . 54 


mm. 
0.35 
.47 
.66 
.89 
1.16 
1.47 


mm. 
0.35 
.47 
.70 
.81 
1.14 
L.63 


mm. 
0.34 
.47 
.67 
.88 
1.18 
1 . 55 


in in . 
i). 12 




.l'ii 


Third 


.21 


Fourth 


.30 


Fifth... 


.37 


Sixth 









THE (OKI. INC MOTE IX MICHIGAN. 83 

The laboratory observations ;tt Douglas, Mich., show thai the mrm- 
ber of molts of the codling modi may vary even under uniform con- 
ditions. The great majority, however, have six larval instars, a few- 
only five, and very exceptionally seven instars. 

Head measurements, when used in a series of consecutive tests, 
will bring out the number of molts of the larvae, but this method can 
not be relied upon in determining the instars of any given larva, 
owing to the variability in size. The final averages as shown in 
Table LXXXI bring out the average widths of the head of the cod- 
ling moth larva in its successive instars and also the rale of increase 
of each molt. 

In 1SS1 Edwards ' pointed out that the number of molts depends 
largely upon climatic conditions, these molts being more frequent in 
warm climates where the growth is rapid than in cold climates where 
the growth is retarded. The present records on the number of molt-. 
of the codling moth in Michigan and in the Ozarks corroborate 
Edwards's statement. Jenne found seven instars in the South, while 
in the North the writer found six instars. 

CANNIBALISM AMONG I.AIIV.E OF THE CODLING MOTH. 

In confinement, when a large number of mat ure codling moth larvae 
are kept together, it sometimes happens that certain larvae will 
attack and kill weaker ones and later devour them. After such a 
feast the cannibal larva assumes a dull, turbid color and can be readily 
recognized from the rest. It is evident that cannibalism among the 
larvae also takes place under normal conditions. It has frequently 
been noted that a number of newly hatched larva^ have entered the 
same apple, but only a single or a few larva' matured in the same 
fruit. Occasionally larva' have been collected from bands which had 
the characteristic, appearance of cannibal larvae. 

CODLING MOTH I.AIIV.E REMAINING TWO SEASONS IN THE LARVAL 

STACK. 

An unusual observation on the duration of the larval stage of the 
codling moth was made in 1909 and 1910 by Mr. K. W. Brauchef at 
Douglas, Mich. In the fall of 1908 a number of larvae were collect ed 
for rearing purposes and for studies to be made the following spring. 
Two of the larva? failed to transform in 1909 and both were alive the 
following spring, 1910. On April 30 one larva had pupated; the 
other larva died June 24. The pupa, too, finally failed and was found 
dead July 18. Considering that the larva left the fruit about Sep- 
tember 1, 1908, or possibly much earlier, we find that one of the insects 

i Psyche, rol. 3, p. 159, 



84 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

remained 20 months in the larval stage without taking food or water 
and that the other specimen remained 23 months in the cocoon as 
larva and pupa. The two larvae had made their cocoons in a large 
glass vial. They came under the writer's observation in 1910. 

The ability of an insect to remain dormant for a whole season and 
to transform subsequently the third season may possibly occur more 
frequently than has been actually observed. Such an adaptation 
would be of particular advantage to the species in surviving adverse 
seasons. 

CODLING MOTH LARV.E FEEDING ON APPLE FOLIAGE. 

To test the feeding habits of the codling moth larvae on apple 
foliage three branches from which the fruit had been removed were 
bagged and on each 10 newly hatched larvae were placed June 10. 
When examined July 20 it was found that in all three bags feeding 
had taken place, and particularly had the tender growths at the tips 
of the branches been eaten. In one of the bags, at the place where the 
same had been tied around the branch, one half-grown dead codling- 
moth larva was found in a cocoon. In one of the other bags one dead 
pupa was found, which was hardly two-thirds the average size. In 
the third bag no insect was found, though there was evidence of feed- 
ing. It may thus be suspected that in cases of total crop failures the 
insect can subsist on foliage in sufficient numbers for the perpetuation 
of the species. 

SUMMARY. 

The present account of the life history of the codling moth in 
Michigan is based upon a series of studies made in 1909, 1910, and 
1911. 

In the course of a year the codling moth in Michigan produces one 
full brood and a partial second. 

In the field the earliest moths of the spring brood commence to 
appear from 5 to 10 days after the apple blossoms drop, and the ear- 
liest larvae of the first brood hatch from 3 to 4 weeks after the petals 
drop. The earliest larvae of the second brood hatch from 10 to 11 
weeks after the petals drop. During exceptionally warm and for- 
ward seasons the second-brood larvae may appear considerably 
earlier, and were, in 1911, observed 8 weeks after the petals dropped. 
This record, however, should be considered very exceptional. 

The time of appearance and the periods of occurrence of the differ- 
ent stages of the codling moth are shown in figure 11, which, with the 
exception of the spring pupal stage, closely represents the seasonal 
progress under average conditions. Figure 20 similarly shows this 
progress in the development of the insect under prevailing warm and 
exceptionally forward seasonal conditions. 



THE CODLING MOTH IN MICHIGAN. 85 

Egg deposition commenced in the cages from ."> to !* days after the 
emergence of the moths, and most of the eggs were laid within 5 days 
after egg deposition commenced. In one instance eggs were laid 23 
days after the emergence of the moth, but as a rule the great majority 
of the eggs were laid within 8 days of the emergence. 

The number of eggs per female varied considerably in the cages — 
on an average, 57 eggs per female were obtained. A single female 
deposited 161 eggs. Under normal conditions in the field the average 1 
number of eggs is unquestionably higher and probably approaches 
80 to 90 eggs per female. 

The average length of life of the moths was found to be 9 days for 
the males and 11 days for the females. Instances occurred when one 
male lived 32 days and a female lived 37 days. 

The length of the incubation period of the eggs varied greatly 
under different temperature conditions. For the first brood the av- 
erage length was 7 days and for the second brood 8 days. The range 
of variation extended from 4 to 16 days. 

The effect of the temperature upon the length of the incubation 
period is shown by a plotted curve in figure 15. 

The length of the feeding "period of the larvae of the first brood 
varied from 17 to 45 days and averaged 25 days for the "transform- 
ing" larvae and 28 days for the "wintering" larva?. Still larger 
variation in the length of feeding was observed in the second brood, 
ranging from 20 to 84 days and averaging 36 days. 

On an average the larvae spun their cocoons and pupated in 7 days. 
This period varied, however, from 3 to 18 days. 

The pupal stage varied greatly under different temperature con- 
ditions, as is illustrated in figure 13. The average length of the pupal 
stage was 18 days and ranged from 1 week to 2 months. 

The length of the first generation, from the time of the appearance 
of the eggs to the time of emergence of the moths that resulted from 
the same, averaged 51 days in 1910. During 1911 the duration of the 
life cycle varied from 2!) to 87 days and averaged 50 days. 

The relative abundance of first-brood and second-brood larva? 
varied from year to year. In 1909 the second-brood larva? surpassed 
the first brood in numbers and constituted 57 per cent of the larva? 
for the season. During 1910, owing to the wide-felt scarcity of apples, 
the second brood only reached one-third the number of the first 
brood. During 1911 the second brood almost approached the first 
brood in abundance. 

Of the first-brood larva? only a portion transformed the same 
season, while the other portion passed the winter in the larval stage. 
During the three years of observation the ratio between transforming 
and wintering larva 1 of the first brood varied from 30: 70 per cent to 



8G DECIDUOUS FRUIT INSECTS AND [NSECTICIDES. 

;,1 ; 19 per cent, respectively, and averaged 36 per ccnl transforming 
larva 1 and 64 per cent wintering larvae. 

The larvae of either brood shod the skin (molted) live times, and 
had thus six "instars." A limited number of larvae molted only- 
four times. 

A hymenopterous fly, Ascogaster carpocapsse Vier., was found to 
parasitize from G to 7 per cent of the larvse of the codling moth. 

Hibernating codling-moth larvse succumb extensively to the cold 
during the winter. From 25 to 35 per cent were found to be killed. 

From the foregoing records of the life history of the codling moth 
and from the variability of results obtained, it is evident that reliable 
data can only be obtained from a large number of observations. 

From the point of view of mechanical control of the codling moth 
the most important observations of the habits of the insect relate to 
the time of emergence of the moths in the separate broods. Such 
observations should preferably be made from carefully conducted 
band records. It is essential that the collecting of larva? from the 
banded trees should commence sufficiently early in the season so 
that the first-appearing larva may be secured . It is also of importance 
to make the collections at regular and frequent intervals (three days) 
and for the entire season. Apple trees of late varieties should be 
selected whenever available. 

On applying the results of this investigation to the present methods 
of controlling the codling moth in Michigan it will be found that the 
poison-spray applications should be most effective when applied at 
the following periods : 

First. — Shortly after the petals drop, to fill the open calyx cup and 
thus destroy the larvae which hatch later. It is the habit of most of 
the first-brood larvae to penetrate the apple through the calyx end. 

Second. — From three to four weeks after the petals have dropped, 
when the first-brood larvae commence to hatch. 

Third. — Ten weeks after the petals have dropped, when under 
normal seasons the first larvae of the second brood commence to 
appear. During advanced seasons the above period may be short- 
ened to nine weeks and only very exceptionally to eight weeks, as 
noted in 1!)1 1. 



ADDITIONAL COPIES of this publication 
it may be procured from the Superintend- 
ent of Documents, Government Printing 
Office, Washington,{D . C,at 15 cents per copy. 




,v_ V . 



~- 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 115, Part II. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PAPERS ON DECIDUOUS FRUIT INSECTS 
AND INSECTICIDES. 



THE ONE-SPRAY METHOD IN THE CONTROL 

OF THE CODLING MOTH AND THE 

PLUM CURCULIO. 



(SECOND REPORT.) 



A. L. QUAINTANCE, 

In Charge of Deciduous Fruit hisect Investigations, 
AND 



E. W. SCOTT, 

Entomological Assistant. 



Issued Nove.mhek 4, 1912. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



B UBEAU OF ENTOMOLOGY. 

L. O. Howard, Entomologist and Chief of Bureau. 

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. 

R. S. Clifton, Executive Assistant. 

W. F. Tastet, Chief Clerk. 

F. H. Chittenden, in charge of truck crop and stored product insect investigations. 

A. D. Hopkins, in charge of forest insect investigations. 

W. D. Hunter, in charge of southern field crop insect investigations. 

F. M. Webster, in charge of cereal and forage insect investigations. 

A. L. Quaintance, in charge of deciduous fruit insect investigations. 

E. F. Phillips, in charge of bee culture. 

D. M. Rogers, in charge of preventing spread of moths, field work. 

Rolla P. Currie, in charge of editorial work. 

Mabel Colcord, in charge of library. 

Deciduous Fruit Insect Investigations. 

A. L. Quaintance, in charge. 

Fred Johnson, S. W. Foster, P. R. Jones, F. E. Brooks, A. G. Hammar, E. W. 

Scott, R. L. Nougaret, R. A. Cushman, L. L. Scott, J. B. Gill, A. C. BAKER t 

W. M. Davidson, E. B. Blakeslee, W. B. Wood, E. H. Siegler, F. L. Siman- 

ton, entomological assistants. 
J. F. Zimmer, W. S. Abbott, W. H. Sill, entomological assistants, employed in 

enforcement of insecticide act, 1910. 
II 



CONTENTS. 



Page. 

Introduction 87 

Experiments in Virginia 88 

The codling moth 89 

The plum curculio 91 

Experiments in Michigan 92 

The codling moth 94 

Experiments in Delaware 98 

The codling moth J00 

The plum curculio 102 

Experiments in Kansas 102 

The codling moth 105 

Summary of results 107 

Conclusions 110 



ILLUSTRATIONS 



PLATKS. 

Page. 
Plate IV. Fig. 1 — Picked apples from three trees of Plat I (demonstration) 
in the Edward Hutchins orchard, Fennville, Mich. 
Fig. 2. — Picked apples from three trees of Plat III 
(one-spray) in the Edward Hutchins orchard, Fenn- 
ville, Mich. Fig.3. — Picked apples from three trees of 
Plat V (unsprayed) in the Edward Hutchins orchard, 
Fennville, Mich 96 

TEXT FIGURES. 

Fig. 23. Diagram showing arrangement of plats and trees in the W. F. Gilkeson 

orchard, near Fishersville, Va 88 

24. Diagram showing arrangement of plats and trees in the Edward 

Hutchins orchard near Fennville, Mich 93 

25. Diagram showing arrangement of plats and trees in the F. C. Bancroft 

orchard, near Camden, Del 99 

26. Diagram showing arrangement of plats and trees in the Thomas fruit 

farm orchard, near Wichita, Kans 103 

in 



U. S. D. A., B. E. Bui. 115, Part II. D. F. I. I., November i, n»12. 

PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



THE ONE-SPRAY METHOD IN THE CONTROL OF THE CODLING 
MOTH AND THE PLUM CURCULIO. 

(Second Report.) 

By 

A. L. Quaintance, In Charge of Deciduous Fruit Insect Investigations, 

and 
E. W. Scott, Entomological Assistant. 

INTRODUCTION. 

The present paper constitutes the second report on the "one- 
spray" method in the control of the codling moth in comparison 
with the usual demonstration treatment of from three to five appli- 
cations according to locality. The previous report on this subject 
will be found in Bulletin 80, Part VII (Revised), pages 113 to 146 
(1911) of the Bureau of Entomology. The experiments herewith 
reported are in continuation of those detailed in the publication 
cited, and have been done in connection with other experimental 
work at several of the bureau's field stations. In addition to the 
insect questions investigated hi a given locality, attention has also 
been given to the control of certain diseases of the apple, this latter 
in cooperation with Mr. W. M. Scott, then of the Bureau of Plant 
Industry of this department. These tests have been made, as in 
the work previously reported, in widely separated States, repre- 
senting a considerable range in climatic and other conditions, and 
were carried out as closely as possible according to a uniform plan, 
for the most part by different members of the force engaged in 
Deciduous Fruit Insect Investigations. The experiments in Virginia 
in 1910 were carried out by Messrs. J. W. Roberts and Leslie Pierce 
of the Bureau of Plant Industry and Messrs J. F. Zimmer and J. B. 
Gill of the Bureau of Entomology. The work in Michigan during 
1911 was under the immediate direction of Mr. E. W. Scott, and in 
Delaware was done by Messrs. W. B. Wood and F. L. Simanton of 
the Bureau of Entomology and Mr. W. B. Middleton of the Bureau of 
Plant Industry. In Kansas, in 1911, the work was carried out by 
Mr. J. B. Gill of the Bureau of Entomology and Mr. Leslie Pierce 
of the Bureau of Plant Industry. 

Since the appearance of the first report of the Bureau of Ento- 
mology on the one-spray method, additional information on the sub- 

87 



88 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



ject has been published by other workers, notably by Prof. W. E. 
Rumsey, in West Virginia Experiment Station Bulletin 127, and 
by Dr. E. P. Felt, in Circular 40 of the New York State Department 
of Agriculture and in the Journal of Economic Entomology for 1911 
and for 1912. The information now available seems to warrant the 
conclusions given in the present paper. 

EXPERIMENTS IN VIRGINIA. 

The experiments in Virginia were carried out during the season 
of 1910 in the orchard of Mr. W. F. Gilkeson near Fishersville. The 
entire orchard consists of 30 acres, but only about three-fourths of 
this was used for the experiments, the remainder being sprayed by 
the owner. The experimental part comprised three plats, as shown 



xxxxxxxxxxxxxxxxxxx 
xxxxxxxxxxxxxxxxxxx 
xxxxxxxxxxxxxxxxxxx 
xxx xxxxxxxxxxxxxxxx 
xxxxxxxxxxxxxxxxxxx 
xxxxxxxxxxxxx xxxxxx 



X X X X X 

®®@© x 

®®®X X 

x (D x x x 
X ®®x X 

X X X X X 



SI 



X X 

\ x 



®® 
®® 
©® 
®@ 



I 



X X X X x^ 

X ®®® X 
®®® X ® 
®® X x ©I 
X X X X X 
X X X X X! 
X X X X X 
X X X X Xy 



Co/V77NUs4T/OA/ OF /?PPL£ OffCM?0 - <4SOVr /S/?OWS. 

Fig. 23. — Diagram showing arrangement of plats and trees in the W. F. 
ville, Va. Trees counted are indicated by circles, the numbers agreeing 
tables. Variety, York Imperial. (Original.) 



Gilkeson orchard, near Fishers- 
with the numbers of trees in the 



in the accompanying diagram (fig. 23). The trees of each plat from 
which the fruit was counted throughout the season for records are 
designated in the diagram by the same numbers which these trees 
bear in the table. The orchard is on a hillside gradually sloping to 
the southeast. It had a good cover crop of June grass and clover 
and was kept clean of dead limbs and rubbish, and the trees are 
headed rather low, thus facilitating spraying. The principal variety 
is York Imperial. There are a few Early Harvest trees scattered 
throughout the orchard, but none of these latter was included among 
the count trees. Plat I included 150 trees, Plat II 64 trees, and 
Plat III (the unsprayed plat) 10 trees, this last plat being in the 
center of the orchard. The treatments which the respective plats 
received are shown in Table I. 



ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 



89 



Table I. — Treatments and dates of applications for the codling moth and the plum 
curculio. One-spray method. Fishersville, Va., 1910. 



Dates of application. 


Plat I. 


Plat II. 
(One-spray method.) 


Plat III. 
(Unsprayed.) 


First application, Apr. 1G-18 
(as soon as petals fell). 


Not drenched. Vermorel 
nozzles. Mist spray. Ar- 
senate of lead, 2 pounds to 
50 gallons commercial 
lime-sulphur (1J-50). 
Pressure, 200 pounds". 

do 


Drenched with arsenate of 
lead, 2 pounds to 50 gal- 
lons commercial lime-sul- 
phur (U-50). Bordeaux 
nozzles. " Pressure, 200-225 
pounds. 

Commercial lime-sulphur 

only (U-50). N o t 

drenched. No arsenical. 

do 


Unsprayed. 
Do. 




.. .do 


Do. 











Plat I was sprayed thoroughly three times but was not drenched. 
Commercial lime-sulphur wash and arsenate of lead were used for 
each applicatoin. Plat II (one-spray method) was thoroughly 
drenched, Bordeaux nozzles and high pressure being used. This 
plat received one application of arsenate of lead and commercial 
lime-sulphur and two subsequent applications of commercial lime- 
sulphur only. 

THE CODLING MOTH. 

In Table II is shown the total wormy fruit and fruit free from 
injury by the codling moth for the entire season for the eight count 
trees of each plat, the number of the trees in the figure agreeing with 
those in the table. 

Table II. — Number of sound and wormy apples for each tree from demonstration, one-spray 
and unsprayed plats . Fisherville, Va., 1910. 

PLAT I. LIME-SULPHUR DEMONSTRATION. 



Condition of 
fruit. 


Tree 
1. 


Tree 
o 


Tree 
3. 


Tree 
4. 


Tree 
5. 


Tree 
6. 


Tree 
7. 


Tree 
8. 


Tree 
9. 


Tree 
10. 


Total 
for 

plat. 


Total 
per 
cent 

of 
sound 
fruit. 


Wormy 


141 
21,324 


29 
9,131 


47 
9,221 


80 
9,445 


35 
8,749 


27 
6,560 


31 

6,373 


72 
6,980 


22 

5,622 


12 
2,566 


85,971 








Per cent sound . 


99.34 


9,100 
99.68 


9, 208 
99.49 


9,525 
99.16 


8, 784 
99.60 


6,587 
99.59 


6, 404 
99.51 


7,052 
98.97 


5, 644 
99.61 


2,578 
99.53 


86,467 


99.42 



PLAT II. ONE-STRAY METHOD. 



Wormy 


82 
7,282 


88 
6,543 


63 
8,044 


63 
7,539 


6 
2,023 


29 
3,372 


33 

3,777 


77 
5,873 


41 
3,065 


23 

3, 127 


505 






Total 
Ter cent sound . 


7,364 
98.88 


6,631 

98.67 


8,107 
99. 22 


7,602 

99.17 


2,029 
99.70 


3,401 

99.14 


3,810 
99.13 


5,950 
98.70 


3,106 
99.68 


3,150 
99.27 


51,150 

99.01 



PLAT III. UNSPRAYED. 



Wormy 


781 
5,159 


423 

1,908 


487 
3,067 


480 
2,935 


355 

1,874 


296 
1,329 


812 
4,413 


188 

1,168 


421 
2,285 


776 
3,227 


5,019 
>7 3tV5 








Total 
Per cent sound . 


5,940 
86.85 


2,331 
81.84 


3,554 
86.29 


3,415 
85.94 


2,229 1 1,625 
84.07 81.78 


5,225 
84.45 


1,356 
86.13 


2,706 
84.44 


4,003 32,384 
80.61 


84.50 



90 DECIDUOUS FBUIT INSECTS AND INSECTICIDES. 

• Plat I, which received all three applications of arsenate of lead, 
gave 99.42 per cent fruit free from codling-moth injury, the per- 
centage for individual trees ranging from 98.97 to 99.68. The total 
number of apples counted from this plat was 86,467. Plat II 
received the one-spray treatment and shows a total of 99.01 per cent 
of fruit free from codling-moth injury, the percentages for individual 
trees ranging from 98.67 to 99.70, and the total number of apples 
examined being 51,150. This shows a difference of only 0.41 per cent 
in favor of the demonstration. Plat III, the unsprayed plat, shows 
84.50 per cent fruit free from codling-moth injury, the total number 
of apples examined being 32,384. This shows a gain in sound fruit 
by the demonstration treatment of 14.92 per cent, and by the one- 
spray method a gain of 14.51. As will be noted, the percentages of 
sound fruit from the check trees is rather high. This is probably 
very largely due to the fact that these were located in the center of 
the orchard, all the surrounding trees being sprayed. 

In Table III are shown the places of entrance into the apple of the 
total larvae for the season for each tree of each plat, and also the 
percentage, by plats, entering the fruit at the calyx, side, and stem. 

There was a total of 496 larvae on the demonstration plat, as 
against 505 larvae on the one-spray plat, a difference of only 9 larvae 
in favor of the demonstration plat. On the unsprayed plat there 
was a total of 5,019 larvae. Comparing the percentages of larvae 
entering at the calyx end of the apple on the different plats it will be 
noted that the demonstration plat shows 33.06 per cent entering at the 
calyx end as compared with 13.46 per cent on the one-spray plat. 
The unsprayed plat shows 63.86 per cent of larvae entering at this 
point, which may be taken to indicate the normal behavior of the 
larvae. 

Table IV shows the comparative efficiency of the demonstration and 
one-spray treatments in preventing infestation at calyx, side, and 
stem. 

By comparing the figures for the different plats it will be seen that 
the one-spray treatment was more effective than the demonstration 
in preventing entrance at the calyx, and less effective in preventing 
entrance at the side and stem. The demonstration treatment saved 
a total of only 0.41 per cent more of the crop than the one-spray 
method, most of this saving being due to prevention of side entrances. 



ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 



91 



Table III. — Places of entrance of fruit by total larvae of tin codling moth for each tree of 
each plat. Fishersville, Va., 1910. 

PLAT I. LIME-SULPHUR DEMONSTRATION. 



Total number of larvae and place of entrance of fruit for each tree, first and second 




Per- 








broods combined. 












cent- 
age of 
larvrc 










1 












Total 




















Total 


enter- 


num- 




















for 


ing at 
calyx, 
side, 


ber of 


Place of entrance. 


Tree 


Tree 


Tree 


Tree Tree 


Tree 


Tree 


Tree 


Tree 


Tree 


plats. 


larva. 




1. 


2. 


3. 


4. 5. 


0. 


7. 


8. 


9. 


10. 




























and 


























stem. 




First and second 


























broods: 
























('alvx 


49 


6 


14 


25 5 


10 


Hi 


32 


4 


3 


164 


33. 06 




Side 


GO 
32 


20 
3 


26 

7 


40 

15 


22 

8 


12 

5 


11 
4 


14 
26 


12 
6 


9 



226 

106 


45. 57 
21.37 












Total 


141 


29 


47 


80 


35 


27 


31 


72 


22 


12 


496 


inn no 


496 



PLAT II. ONE-SPRAY METHOD. 



First and second 
broods: 

Calyx 

Side 

Stem 

Total 



8 


11 


6 


7 


1 


4 


12 


45 


49 


42 


30 


4 


14 


17 


29 


28 


15 


26 


1 


11 


4 


82 


8S 


63 


63 


6 


29 


33 



4 


4 


68 


13.46 


26 


13 


280 


55.45 


11 





157 


31.09 


41 


23 


505 


100.00 



505 



PLAT III. UNSPRAYED. 



First and second 
broods: 

Calyx 

Side 


4S7 
132 
162 


252 
78 
93 


297 

ss 
in.' 


."in 
100 

SI 


244 
60 

.->1 


196 
58 
42 


561 
93 
15S 


111 
43 
34 


251 
62 

HIS 


510 3,205 
in;, 819 
161 • 995 


1 

63.86 1 
16. 32 
19.82 












Total 


781 


423 


487. 


480 


355 


296 


812 


188 


121 


770 5,019 


100.00 . 


5,019 



Tablk IV 



Efficiency of the demonstration <m<l one-spray treatments ox shown by the 
percentage of wormy apples . Fisher sville, Va., l.)W. 



Plat No. 



I. Demonstration 

II. One spray 

III. Unsprayed 



Percentage of wormy apples. 



Calyx. 



0.19 

.13 

9.89 



Side. 



0.26 

.54 

2.53 



Stem. 



Total. 



0.12 

.31 

3.07 



0.57 

.98 

15.49 



Total 
number 

of 
wormy 
apples. 



496 

505 

5,019 



Total 
number 

of 
apples. 



86, 4H7 
51,150 
32,384 



THE PLUM CURCULIO. 

Table V shows the effect of the treatments in the W. F. Gilkeson 
orchard in controlling the plum curculio on the three plats. Egg 
and feeding punctures are combined in the table under " Number of 
punctures." 

■35743°— Bull. 115, pt 2—12—2 



92 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table V. — Injury by the plum curculio for entire season. Plats I, II, and III. Fishers- 

ville,Va., 1910. 

PLAT I. LIME-SULPHUR DEMONSTRATION. 



Number of punctured and sound apples, etc., per tree in each plat. 


Total 
for 
plat. 


Total 
per 




Tree 
1. 


Tree 
2. 


Tree 
3. 


Tree 
4. 


Tree 
5. 


Tree 
6. 


Tree 

7. 


Tree 
8. 


Tree 
9. 


Tree 
10. 


cent of 

of fruit 

free 

from 

injury. 


Number punctures 

Number fruit punc- 


1,333 

987 
20,478 
21,465 

95.40 


677 

321 
8,839 
9,160 

96.49 


618 

397 
8,871 
9,268 

95.71 


747 

471 
9,054 
9,525 

95.05 


864 

522 
8,262 
8,784 

94.05 


757 

483 
6,104 
6,587 

92.66 


835 

476 
5,928 
6,404 

92.56 


819 

542 
6,510 
7,052 

92.31 


369 

239 
5,405 
5,644 

95. 76 


210 

123 
2,455 
2,578 

95.22 


7,229 

4,561 
81,906 
86,467 




Number sound fruit 




Per cent free from in- 


94.72 







PLAT II. ONE-SPRAY METHOD. 



Number punctures 

Number fruit punc- 
tured 

Number sound fruit 

Number fruit 

Per cent free from in- 
jury 

Number punctures 

Number fruit punc- 
tured 

Number sound fruit 

Number fruit 

Percent free from in- 
jury 



855 


1,025 


563 


744 


113 


271 


231 


314 


149 


223 


4,488 


428 
6,936 
7,364 


584 
6,140 
6,724 


544 

7, 563 
8,107 


516 
7,086 
7,602 


107 
1,918 
2,025 


156 
3,245 
3,401 


143 
3,667 
3,810 


202 

5,748 
5,950 


90 
3,015 
3,105 


112 
3,037 
3,149 


2,882 
48,355 
51,237 


94.20 


91.31 


93.28 


93.21 


94.71 


95.41 


96.24 


96.60 


97.10 


96.44 





94.37 



PLAT III. UNSPRAYED. 



917 


311 


332 


483 


231 


168 


683 


146 


342 


620 


4,233 


673 

5,267 
5,940 


246 
2,085 
2,331 


297 

3,257 
3,554 


344 

3,071 
3,415 


165 
2,064 

2,229 


128 
1,497 
1,625 


463 
4,762 
5,225 


81 
1,275 
1,356 


283 
2,423 
2,706 


434 

3,569 
4,003 


3,114 
29,270 
32,384 


88.67 


89.44 


91.64 


89.92 


92.59 


92.12 


91.13 


94.02 


89.54 


89.15 





90.38 



On the demonstration plat the percentage of fruit uninjured by the 
curculio was 94.72, and on the one-spray plat 94.37, which shows only 
0.35 per cent in favor of the demonstration plat. The unsprayed 
plat shows 90.38 per cent free from curculio injury. As has been 
noted, the check trees were in the center of the orchard and sur- 
rounded by sprayed trees, which no doubt accounts largely for the 
high percentage of sound fruit on the check plat. 

EXPERIMENTS IN MICHIGAN. 

The experiments in Michigan during the season of 1911 were carried 
out in Mr. Edward Hutchins's orchard near Fennville,